Notes from Horticulture Class 6 – Saving Seeds

Heirloom. Varieties grown in certain regions, that have stayed the same for generations. People swap and share seeds and the variety becomes indigenous, specific to a region because they perform well in specific climate or soil conditions.

Good example is Daniel O’Rourke Pea.  Perfect round and delicious green peas in a pod! Daniel O’Rourke Pea is considered an Irish heirloom from the 1800s by Irish Seed Savers Association. They found this long lost variety preserved since 1921 at the Vavilov Institute for Plant Industry in Russia, and brought it back into cultivation and circulation in Ireland. It was named after a winning British thoroughbred racehorse, perhaps because it was known as the earliest pea cultivar at the time. The horse was named after a character in an Irish folktale who was carried to the moon by an eagle. Some report that this is the same pea as horticulturalist, breeder, and seedsman John Sangster’s “Sangster’s No. 1 Pea”, a very popular variety in the mid- and late-1800s on both sides of the Atlantic. It is used as a fresh shelling pea, and also as a dry pea for soups. Thanks to Irish Seed Savers for this seed, and to artist Christine Mackey for her research on this pea’s history.

Back in history, most seeds were local to communities. Of course as society evolved, railways and transport allowed people to move around, seed varieties became commercial products and more widely used.  

Most Heirloom seeds are Open Pollinated. “Open pollinated” generally refers to seeds that will “breed true”. When the plants of an open-pollinated variety self-pollinate, or are pollinated by another representative of the same variety, the resulting seeds will produce plants roughly identical to their parents. (Wikipedia)

So the genetics of Heirloom seeds are quite stable. For example, the Daniel O’Rourke pea has been tested from one generation to the next over many years and shows no change.

It should be said that change can and will occur in Heirloom seeds – as Open Pollinated seeds have the ability to adapt their genetic structure to changing climate conditions. This change will happen over multiple years, responding to changes such as average temperatures, rainfall etc.

Example of Open Pollinated seeds:

MUSSELBURGH LEEK. The Musselburgh leek was originally imported from France and first cultivated in the town of Musselburgh in Scotland. This area of Scotland is not renowned for its mild weather and this variety of leek is perfectly suited to the very cold winters in this area. The same inherent genetic structure (ignoring changes in response to climatic conditions) will have existed for over 100 years.  

Open Pollinated seeds are available from niche suppliers who offer varieties that are not usually found in the mass market retail trade. Examples:

Brown Envelope Seeds (West Cork)

Real Seeds (Wales)

W. Robinson & Sons  (Seeds and Plants)  See Heritage Pages

Irish Seed Savers Association (Clare)

Hybrid F1

The mass market seeds most commonly found in retail and online stores are Hybrid F1.  These seeds are generally combinations of two different species of plant which are crossed to produce an offspring that delivers specific characteristics such as higher yield, sweeter, uniform shape or taste, ease of processing, size, uniformity of ripening/harvesting. These characteristics are often targeted at commercial growers who want to optimize harvesting costs and shape to meet retailers’ quality (sic) requirements. These of course are frequently in direct conflict with the objectives of small growers who look for staggered ripening and harvesting.  

Crossing two genetically different plants produces a hybrid seed. This can happen naturally, and includes hybrids between species (for example, peppermint is a sterile F1 hybrid of watermint and spearmint). In agronomy, the term “F1 hybrid” is usually reserved for agricultural cultivars derived from two parent cultivars. These F1 hybrids are usually created by means of controlled pollination, sometimes by hand-pollination. For annual plants such as tomato and maize, F1 hybrids must be produced each season. (Wikipedia)

In summary, Hybrid F1 is essentially a form of genetic modification. And it is very difficult to retrieve a heirloom variety once it is lost along with the skills. If you save Hybrid F1 seeds you will not get the same results in the second year. It is likely the crop will be lower in quantity and or quality.

Evidently we have lost 80% of the Heirloom varieties over the past 50 years. It’s also important to note that the major seed producers are huge corporations, often bringing seeds to market under numerous well-known brand names such as Suttons, Unwins etc. Clearly we have become very dependent upon just a very few large corporations which concentrates skills and knowledge in relatively few heads that you might consider represents a risk to our ability to feed ourselves.  

In contrast, saving our own seeds allows us to have control and independence over our entire growing process.

Saving Seeds

Annuals (peas, beans, tomatoes, sweet pea etc) can be saved in one life cycle (6 – 8 months).  These seeds are genetically stable and produce the same results year after year. Annual seeds will last literally thousands of years. (E.g perfectly usable seeds were found in the pyramids of Giza!)

Tomatoes very easy to save – take a jam jar, some water, squeeze the tomato and it will release its seeds. Cap and shake the jam jar, leave for 3 – 5 says. The acid in the tomato breaks down the gelatine around the seed and allows the seed to separate. Leave for further 3 days. Pour into sieve, wash and allow to dry. Then pick off seeds into a brown envelope.

When saving seeds, select plants to save from that are healthy, ripe, vigorous. Have no disease, pest damage.

Biennials – Onions, brassicas etc

After harvesting onions – store best examples. Not from bolting plants. Plant out in spring next year and allow to go through to flower.  Collect seeds.

Same for carrots, parsnips, beetroot. Note carrots will grow in 2nd year to huge size (6’ x 4’)

Harvest seeds when the plant is fully ripe and when dry so seeds have little moisture. Cut flowers and leave lying in a tunnel to dry. The objective is to achieve a balance between losing moisture and yet not fully drying out. Store in brown envelopes or glass jars. Brown envelopes are best.

The seed is still a living part of the plant. But the moisture content has dropped so low that growth has almost stopped. Need to keep cool and dry, but not too dry.

There are differing requirements for specific seeds, see sample references below.

University of Minnesota Saving Seeds

Gardening Knowhow – Storing Seeds

RHS Seed: collecting and storing

US Dept. of Agriculture

United Nations Seets Toolkit

Johnny’s Selected Seeds – Storage Guide


Question: Tomato ripening but browning. Why?

Answer: Probably giving it too much water. Remember tomatoes come from Mexico, and they don’t have a lot of water. Water 1litre every 3 days is sufficient.

Notes from Horticulture Class 5 – In the Weeds

Actually “weeds are not all bad”. After preparing the soil it doesn’t do any harm to leave young, small weeds such as redshank, chickweed etc to grow, and it facilitates retention of moisture. Additionally young weeds don’t harbour pests and or diseases until they are around 6 – 8 weeks old. Many annual weeds are also edible – e.g chickweed, lambs quarter, red shank (well IMHO that’s debateable), dandelion and nettles. The latter two of course very difficult to eradicate if left too long.

Weeds are also full of nutrients and will enrich the soil if left to decompose on the ground or provide good base for fertiliser. Ideally weeding is done on a wet day – hand weeding carefully pulling weeds including the roots. Need to be removed, otherwise if left on the soil damp they will survive to grow another day.

Similarly don’t create a heap of weeds for the same reason – some will survive. Better to remove and use to make a liquid feed or put in the compost bin as all nutrients are useful. Otherwise you are probably just putting your own fertiliser back into the bin!

On dry days a short hoe is recommended. Never hand weed where a hoe can reach. Recommend an oscillating hoe – with a swivel head and double, D shaped blade that cuts on both forward and backward movements. Best time on a dry day is mid-afternoon, when the air rises with the heat from the sun (well this is Ireland) and creates breeze that dries the roots. These roots can be left in situ and act as an excellent mulch.

Question: What is the nutrient mix of types of weed?

All plants contain the same nutrients. Just some break down faster and easier than others. In general leafy plants will have more N than P and K. In their early stages of growth they will all have a mix of all macro and micro nutrients. Weeds also contain water and Carbon. Nettles have more N. Note here the Latin name for nettles is Urtica dioica – from which we might assume Uric acid is derived which is high in N. Hence the “stinging” nettles.

In contrast Comfrey is high in P and K. The Comfrey roots are deep (question to self, are nettle roots shallow, yes of course!) and therefore take nutrients from deep down in the soil. Dock would have the same nutrients as Comfrey, BUT the reason we like the latter is it’s leaves are far easier to dissolve in water.  The leaves would also be generally high in chlorophyll. The N high stems tend to be structural and cellulose – higher in carbon; and less easy to break down. (I did interject here, that I do use the stems of Comfrey in the tea bin, primarily because the extended immersion in water greatly softens the stems and acts as a precursor stage for composting.

Lot of discussion about how to know what nutrient proportions the tea will have. Danger of “overloading” which will produce undernourished plants, sickly discoloured leaves and plants that we more susceptible to pest attacks. Overloading may also lead to lush growth – plants that are not strengthened in proportion to their size, and which do not mature properly. In onions, bulbs may be large and full of sap. Carrots may fang (excess N).

Rule of thumb (for tea making ) is 10:1 won’t go wrong.

In general don’t over feed plants. It’s easier to pinpoint under nourishment than over nourishment.

When planting in the Spring it’s a good idea to break the surface of the soil to allow weeds to germinate – using up the weed seeds all at once. Allow the weeds to get to about 1” or so and then just before sowing, remove weeds. Call this a “stale weed seed bed”. (I like that).

Alternatively kill off weeds mechanically with hoe (as discussed) or blow-torch!!! Using a small torch (roofers) is a good way to kill weeds. Further it sterilises the soil. And evidently organic growers are moving into burning, particularly because it doesn’t disturb the soil, and therefore allow weed seeds to surface. (No dig method). Now it might also kill/damage good bacteria, and the jury’s out on what is the best approach. Called “flaming”. (Nothing to do with over enthusiastic social media activity).

 Other ways of killing weeds involving some form of mulching:

  • covering with clear polythene after weeds germinate  – heat of the sun kills and sterilises. Use tunnel cover polythene. Make up wooden frames the size of beds and cover. Try the Co-op for polythene.
  • “weedblock” membranes.
  • also cardboard works well for larger plants such as brassicas. Might need to install a watering system – e.g weepy pipes or (better) holey bottles as small reservoirs.
  • leaf mould (high in N)
  • checkout geeup (composted horse manure very good for mulching). Locally made in Blarney.

The advantage of mulching is that it retains moisture – whereas if you just strip weeds the soil dries. Use mulch particularly for shrubs (fruit?) and permanent crops.

Speaking of mulching . . . Consider a separate compost bin for leaves. Keeping separate is probably best in order to keep brown and green matter in proportion. Leaves are quite sterile and v dry and break down better if kept separately. (Living green leaves are considered “green materials”, whereas the dead, dry leaves that fall from the trees in autumn are seen as “brown materials”. Autumn leaves are a great source of carbon and contain a surprising amount of nutrients that can be returned to the soil through compost.)

Discussed several options for weed block – mypex, non biodegradeable covering material. Woven weed block. Non woven – oil based doesn’t fray. Sheeps wool – quite thick, light and degrades slowly over 2 seasons. Also can use hemp/cotton fibres, woven better than sheeps wool – they tend to be denser and don’t allow light through. However this can be expensive  (like €3 / sq m). Double the cost of weedblock.

Re non biodegradeable blocks, we need to consider the “end of life” cost. In general we need to be investing a little more upfront in order to avoid end of life costs (not just our landfilling charges but the cost to the environment in the long term). Biodegradeable is clearly the way to go.

For all these materials checkout the garden shop.

. . . or fruithill farm. (West Cork based organic pioneers).

Finally a good layer of seaweed. The trick with seaweed is to keep it moist. Mix with normal peat moss helps to retain moisture. And apart from the peat moss, it’s free if you go and collect it!

Next week: Harvesting seeds and everything about seeds!!

Notes from Horticulture Class 4 – Planting and Companion Planting

The Three Sisters Companion Planting Pattern

Planting generalities

Planting is a succession of activities requiring decisions on timing and quantity. At the heart of this is timing.

Think about plants in two sets – tender and hardy.

Hardy plants can be planted before the last frosts in spring (mid May) and will include brassicas, potatoes etc. While frost will burn potato leaves they will not be badly damaged.

Tender plants should only be planted out from June onwards. Planting out from seed not advised until there is no risk of frost, irrespective of seed type. Soil temperature should be at least 10 and if possible 12 degrees. Generally mid to end May.

Root crops are generally sown direct into the ground in tunnels or with some protection. Some varieties can be outside but most will be inside in mid May.

Plant seeds outside end May and into June. There’s always temptation to plant too early. But time is better spent tidying or preparing the ground. Plantings of  carrots, parsnips and turnips in early June will always catch up with earlier sowings.

Tender plants such as pumpkins or squash should be planted in tunnels and planted out 2 – 3 weeks later. If plantings are too early they may “sulk”. Not showing any growth. Recommend delay sowing seeds so that planting out happens in June.   

Provide heat in cool weather by using cloches – e.g use 10 – 20L water bottles, with bottom cut off for single plants. Or storage boxes.

Alliums (onions, shallots, etc) bulbs are fully hardy – can be planted into the ground in autumn when < 10 degrees, or in spring when soil is a cool 6 degrees. But note, onions grown from seed need minimum 12 degrees.

Corn on the Cob

Need good flowers – Male and female. Male flowers are at the top of the plant. Female flowers midway down the plant where the cobs will form. Pollen falls from the Male to the Female. Like any flowering plant corn need P and K. Not so much N.  Use comfrey tea plus seaweed. Or use a general tomato feed.

Companion Planting

Companion planting has been practised for thousands of years – longer than today’s commercial “mono planting” practised by commercial growers. Mono planting evolved at the same time as mechanisation in the 1700’s – enabling large plantations of single crop. Prior to that companion planting was the de facto approach.

Where mixed crops are growing together every plant needs light, shelter and nutrients. Low growing crops with bigger crops with higher leaves, e.g corn and squash, will need to be spaced out to allow the squash to grow on the ground and suppress weeds. In this pattern add sunflowers and runner beans, where the runners use the corn for support. Four different plants in one plot. Beans, corn and squash are referred to as the “three sisters”. Native Americans used that system for generations.

The growing pattern is also nutrient symbiotic. The Beans are N fixers producing N that the corn consumes. Squash consumes P and K. None of the three plant types use an excess of nutrients to the detriment of the others.

Into this pattern you can add Nasturtiums. These attract bees that help pollinate the squash and corn. In this pattern corn spacing will be 24” rather than the mono crop spacing of 16”. Generally it is advised to grow as big as corn crop as possible – to ensure pollination happens and also to provide natural shelter. A minimum size corn crop would ideally be 5m x 1m. (full typical raised bed). This would be 24 corn plants.   In practice smaller crops are of course feasible but hand pollination might be necessary (shake the plants or use an old paint brush).

Similar CP pattern might be:

  • Carrots and Onions,
  • General root crops such as beets, carrots, onions.

Carrots, onions and Leeks. Where carrots are deep rooted, onions are shallow rooted and leeks happily grow with the others.  Also can add beet all spaced appropriately. Further benefit is the smell of leeks deter carrot fly.

Just need to remember the rules of CP – ensuring adequate space, light, nutrients for all of the component plants.

Note squash would not work as the leaves are too big and block out the sunlight.

Further thoughts on CP

Companions can

  1. repel insects and pests
  2. attract beneficial insects.


Marigolds under tomatoes – smell of marigolds masks smell of tomatoes and deters white fly.

Garlic and carrots – deters carrot fly

Nasturtiums around apple trees – deters woolly aphids, attracts bees

After 3 years Nasturtiums kill off all woolly aphids.

Deter slugs with:

  • marjoram
  • herb Robert (make extract and spray)
  • ginger (make extract)
  • Horse chestnuts (collected prior year, crush and sprinkle around beds)
    note quite potent
  • Cyclamen – liquidize or chop finely and sprinkle

Attract pests – with sacrificial crop

  • Protect Hostas from slugs – plant sacrificial lettuce nearby
  • Protect potatoes from wire worms – plant Cara variety potatoes (remember you can spread wireworms on your tools) 

What should not be planted together?

  • Carrots and beans (compete for light)-
  • Beans and peas  (compete for light?)

Managing Rotation by (Classifying) Groups (Continued)

22nd June. We continued from where we left off last week with crop rotation. We discussed a basic 7 year (plot) rotation. This of course could extend to 10 years, particularly for organic farmers who might well use the addition 3 years for grassland. But the length of rotation is highly variable and specific to individual circumstances. For example, some organic farmers do 3 and some do 5 year rotation.

Question: How does this relate to smaller areas such as the ones we are managing?

Answer: A full plot of 80 – 100 sqm can easily be divided up into 7 areas. Smaller areas could be divided similarly. Consider a typical raised bed will be 3 ft wide and 4.8m long. So you have logically up to 5 sqm available, each sqm could be divided up and be a unit of rotation. So if you have 2 raised beds of 5 sqm you can have 7 rotating areas plus 3 non rotating areas for perennial crops such as strawberries, fruit, artichokes, asparagus etc. 

Now this is the basic theory. But rotation is all about minimizing risk. And doing full rotation is essential for large, commercial scale, whether conventional or organic. Because if a crop fails on a large scale it is a financial disaster. But for individuals, non commercial growers, allotment holders it’s not so critical. So in smaller scale you really should rotate potatoes every year, (see below) whereas after that rotation is not so critical. Rotation can add complexity and stress. The reason we practice rotation is because we are tryintg to intervene in the life cycle of pests and diseases.

Example – with potatoes, if wire worms get established it takes 7 years for them to die off naturally.

Example – main problem with brassicas is club root disorder – affecting cabbages, cauliflowers and broccoli, where the roots don’t form properly because they are unable to absorb nutrients. To counter this you need to adjust the Ph level to be greater than average to deter the disorder. The problem is that if left over plants grow up among the next generation, then the next generation may inherit problems.

This is particularly true of problems such as blight. Wherever you acquire them, seed potatoes are always 2nd generation. So every potato will have some spores of potato blight. Evidently, they cannot be guaranteed to be blight free. In addition, of course blight spores will naturally be disseminated on the wind.

Now the main impact of blight is that it prevents bulking up – so it’s is generally not a problem with mature potatoes. Inevitably all potatoes get some blight. When harvesting some spores will fall off the leaves, so if the next crop is planted in the same place the new crop will have blight from the very start.

We are all familiar with last year’s potatoes that were grow from small potatoes that were left behind in the soil when lifting the crop. We call these “volunteers”. You can perhaps recognize these plants and not allow them to develop but they do harbour blight from the last crop and are vectors that introduce problems into new crops. This doesn’t happen if the crops are rotated.

Still talking potatoes, recommendation – sow earlies mid / end March – they will mature around 70 days say mid July. Blight warnings are most prevalent end June early July. At that time Earlies are mostly mature and will not be seriously impacted.

The other strategy is to plant blight resistant or tolerant varieties.

  • Resistant = doesn’t get blight at all
    • Tolerant = no effect on crop

But most people will be guided by taste. The resistant and tolerant varieties are generally regarded as being lower quality in terms of taste.

[Sidebar: breeding new varieties in all types of crop doesn’t appear to take quality into account. Consider modern wheats that contain far more gluten than traditional wheat and therefore cause problems for consumers.]

Question:  What about potatoes and slugs and wireworms?

Answer: Slugs shouldn’t be a problem. Slugs are digesters – they eat excess vegetation and return it back to soil.  If we don’t have excess vegetation in terms of weeds, slugs will try elsewhere. Slugs will survive if we give them places to hide – bags of compost, timber edges, stones, grassy margins, weeds.  Encourage natural predators – foxes, frogs, hedgehogs etc. Note slugs can travel hundreds of metres. Only way to deal with them is in bucket of salty water.

Environmentally friendly slug pellets may not be so environmentally friendly if they kill the birds that eat the slugs! Use coffee grounds, beer, copper strip etc.

Ireland is supposed to be certified free of wireworms! However wireworms are easily reintroduced via vegetable shipments for supermarkets, introduced soil and or compost. Removal method – cover soil with black plastic/matting. Wireworms will congregate underneath. Lift and remove. Margaret Griffin says do very frequently to eradicate. Advice – don’t touch with hands – irritant.

Flatworms are increasing problem imported from NZ and Australia in pot plants. Flatworms prey on our earthworms. Length from 1.25 to 4/5 ins. Flatworms may be orange  or dark brown with mottled while/cream markings.

Potential solution for pests is Nematodes. Pest/disease specific solution. One little bacteria to kill pests. However difficult to obtain and not cheap.

Returning to rotation, many forms of rotation may be suitable for circumstances, size of plot, range of crops to be grown. We will consider Companion Planting for smaller scale next. To be continued  . . . .

Managing Rotation by (Classifying) Groups

  1. Potatoes – Solanums

Easy crop to grow. Options:

1st Early – 70 days to mature

2nd Early – 85 days  . . . .

Main Crop – 100 – 110 . . . . .

Preparation – in November for following Spring

  • Add farm manure to soil, dig and cover
  • This process can be carried out at any time over the winter, up to 4 weeks before mid March. Even a short time of prepared, covered soil is beneficial in eliminating weeds

Before planting

  • Dig, fork, add general purpose fertiliser (7 – 6 – 17)
  • Harvest July, then option to plant in same space winter brassicas – brussel sprouts, broccoli, winter cabbage etc.

Alternatively harvest main crop September

This will be too late to plant winter brassicas

Cover ground (as above) and leave idle for the winter.

2. Brassicas

Brassicas over wintered, then plant . . .

3. Onions (Alliums)

Plant either autumn or spring.

Add general purpose manure pellets at beginning

When fully grown feed with horsetail liquid / chicken manure pellets

Lift for next crop

4. Root Crops

Parsnips, carrots, beetroot, celeriac etc

Add super phosphate (very low or no N) to promote deep roots

Turnips etc planted in June in warm soil conditions. At least steady 12 degrees. Note don’t plant too early.

Note 1 soil thermometer is not expensive and helpful to check and record soil temperature.

Never plant fresh farmyard manure – causes fanging (multiple roots caused by excessive N)

Next crop . .

5. Legumes (peas, beans etc)

Note many people make the mistake of planting too early.  Most crops mature in 70 days.

Option to overwinter beans and peas (meteor v hardy variety)

It may be necessary to protect from harsh wind or wet (slugs)

No N required. Legumes provide their own. Use 0 – 7 – 30

When peas growing and starting to flower add tomato food to encourage flowering once a week. Peas like a lot of moisture.

Note: It can be difficult to buy specific fertilisers in smaller quantities. Consider bulk buying and storage?

To be continued . . .

Soil Analysis

Soil pH or soil reaction is an indication of the acidity or alkalinity of soil and is measured in pH units. The pH scale goes from 0 to 14 with pH 7 as the neutral point. Various analysis tools:

  1. Basic test kits are cheap and readily available based on indicators or dyes. Many dyes change color with an increase or decrease of pH making it possible to estimate soil pH. In making a pH determination on soil, the sample is saturated with the dye for a few minutes and the color observed. But they are unreliable and it can be hard to interpret the result. (Cheap)
  2. Simple Ph meter =is a chemical kit  -canister into which powder and watery soil.  (Cheap)
  3. More accurate pH measurements are obtained with a digital pH meter. A pH tester system consists of three parts: a pH probe, a reference pH electrode, and a high input impedance meter. The pH meter is basically a high impedance amplifier that accurately measures the minute electrode voltages and displays the results directly in pH units on either an analog or digital display.  (+/- €20)
  4. Analysis Service. Take samples and send to a lab. (Expense dependent upon number of tests) Example – Southern Scientific, Kerry. See per test €14.

Recommend 5 or 10 samples at random – avoiding parts of the test area that are atypical. Measure below the top 3” – where roots will be. Remove stones etc. Repeat 10 times, then mix together and test.

Best time to test is in the autumn. In general it would be expected that a result of 6.5 Ph would be optimum.

A second for of test – Soil Texture Test.

Get big jar or glass cylinder or Perspex pipe with blank end, 1.5 ft long, 50 ml diameter.

Fill with soil and water roughly 50:50. Shake and let settle, anywhere between a day and a week. A mic with high clay will take longer. When the water is crystal clear the solids have will have settled into strata with heavier matter (clay) at the bottom and lighter matter (organic material) at the top. Inspect stratification and assess proportions and then requirement to adjust.

Note soil analysis kits will usually include a table of Ph adjustments to make to achieve certain outcomes. In general soil analysis should be carried out once every 4 – 5 years. Note don’t attempt to fix soiuld characteristics all at once, but over a period of 3 years.

Guidance notes:

  • Soil Ph will vary across an area.
  • Aim to establish an average using a general purpose fertiliser, and then add plant specific feed as necessary for the different groups of plants.

Finally, consider a soil temperature meter facility also.

Notes from Horticultural Class – June 15, 2020

Soil Test Kits

  • Soil Test Kits are “Hit and Miss”
  • A PH meter is most reliable
  • A laboratory in Kerry called Southern Scientific will test soil for PH, Phosphorous, Potassium, and Lime requirements.  The cost for this test is = 14.00
  • The Best time to test soil is in Autumn

Testing Soil Texture:  proportion of sand, silt, and clay

  • Use a mason jar or clear cylinder
  • Fill half way with soil, the rest of the way with water
  • shake and let settle for one week
  • You will see stratified layers of material. Sand will be at the top, silt in the middle, and clay at the bottom.  Measure each layer in millimeters, this will give you their proportion in the soil.

Soil in General

  • It is important to identify the soil PH, as well as the soil texture.  This will help determine how to amend the soil (adjust the PH, add specific nutrients) for a particular area based on what you intend to plant in that spot.
  • To increase PH, add lime, but this should be done gradually over time, up to three years.

Working with Plant Groups

  • Potatoes: 
    • one month before planting, add farm manure to the plot, dig it into the soil, and cover with black plastic.
    • An option is to add potato fertilizer with equal parts nitrogen and phosphorous, and half again as much potassium (2:2:3, 3:3:5, 7:6:17)
    • After first early potatoes are harvested, you can plant winter brassicas in the same spot
  • Alliums:
    • adding fertilizer pellets such as chicken manure to the soil is sufficient prior to planting
    • Once established, a liquid fertilizer of horsetail and seaweed sprayed on he leaves is sufficient
  • Root Crops
    • Only plant in the Spring
    • Root crops need a soil temperature of 12 degrees to flourish
    • Don’t add fresh manure to root crops – it will add too much nitrogen
    • Root crops need phosphorous for root development
    • Wait until soil temperature rises in May to plant carrots
  • Legumes:
    • You can plant overwintering beans and peas, planting in September or October
    • Meteor peas is a hearty variety for overwintering
    • They must be protected from wind, frost, and slugs
    • As beans and peas are growing and flowering, you can add tomato food (4:5:8) on a weekly basis
    • Peas like moist soil, do not let the soil dry out
    • Ensure prior to planting that the soil has sufficient manure or compost to prevent it from drying out

Horticultural Class Notes from June 8, 2020


  • Compost and manure make soil workable, but you only need 5% of this in your soil
  • Horticultural Sand is necessary to make the soil workable 
  • Heavy soil (clay) can be difficult to drain
  • Raised beds help counteract the effects of heavy soil


  • Manure can help the soil retain moisture
  • Manure is high in nitrogen which most plants need
  • Nitrogen, Phosphorous, and Potassium are key ingredients to fertilizer
    • Nitrogen produces leaf growth (Lettuce, Chard, Spinach, Kale, Rocket) and bulbs (garlic, onions, leeks)
    • Phosphorous is critical for root vegetables (potatoes, carrots, beets, Swede).  Potatoes, carrots, beets (root crops) don’t like excessive nitrogen 
    • Potassium produces good flowers, and is necessary for fruit bushes, courgette, cucumber, and other flowering plants
  • Do not add nitrogen to Alliums after mid summer (Onions, Leeks, Garlic).  They won’t mature, won’t dry out, and will rot in storage

Liquid Fertilizer

  • Nettle Tea is very high in nitrogen. Seaweed, banana peels, and egg shells can be added to nettle tea to increase the phosphorous and potassium and balance the nutrients.  Dilute 1 part tea to 10 parts water and apply to plants weekly.
  • Horsetail Plant can be made into liquid fertilizer and sprayed onto the leaves of Alliums (dilute 1 part tea to 4 parts water).

Soil Acidity (PH)

  • Aim for a PH level of 7, which accommodates most plants
  • Add lime to increase the PH level.  Do not use builders lime, use agricultural lime (powder)
  • Peat and Peat Moss lower the PH and increase acidity of the soil
  • Fruit bushes like acidic soil (blueberries around 5, others between 6.0-6.5).  They should be fertilized with low nitrogen, higher parts of phosphorous and potassium
  • Potatoes grown in lower PH soil (more acidic) will have scabs, but will be fine to eat

Crop Rotation

  • Crops should be rotated on a 4 year cycle from plot to plot
  • It’s good practice to leave a plot fallow each year. Cover with seaweed, compost, or straw and then with black plastic.
  • Group plants by class, and the soil conditions they prefer
    • Plant Alliums together (onions, leeks, garlic)
    • Plant Solanales together (potatoes, tomatoes, peppers)
    • Plant Brassicas together (Kale, Swede, Rocket, carrots)
    • Plant Beans and Legumes together (Beans, Peas)
    • Plant lettuce, spinach, chard and beets anywhere
Plant ClassPlantsFertilizerSoil Conditions
SolanalesPotatoes, tomatoes, peppersHigher phosphorous and potassium, lower nitrogenBalanced (around 7)
AlliumsOnions, leeks, garlicAdd moderate levels of nitrogen to the soil; use horsetail liquid fertilizer on leavesBalanced (around 7)
Brassicas, Others Kale, swede, rocket,carrots lettuce, spinach, chardHigher phospherous for root growth; higher nitrogen for leaf growth (can apply via liquid fertilizer)Balanced (around 7
Beans and LegumesBush beans, peasNone needed; they add nitrogen to the soilBalanced (around 7
Fruit BushesGooseberry, currant, blueberryHigher potassium for flower growth; sulphate of potash at 1/2 oz per sq yd; or blood, fish, bone meal at 1.25 oz per sq ydSlightly more acidic soils (Blueberry likes PH 5)
Notes taken by Michael Loehr

Crop Rotation Primer

Continuing the notes from the first horticulture class, the final topic moved from the topic of soil improvement to crop rotation. The topics are of course inextricably connected because generic groups of plants require similar conditions and may leave the soil in an appropriate state for the next rotation.

Crop rotation is the practice of growing a series of different types of crops in the same area across a sequenced of growing seasons. It reduces reliance on one set of nutrients, pest and weed pressure, and the probability of developing resistant pest and weeds.

The four generic groups are rotated in the following sequence:

  1. Brassicas (cabbage, cauliflower, broccoli, kale, turnip etc)
    like high Ph – 6.5 to 7.5. Add lime.
  2. Alliums (onions, leeks, garlic, chives, shallots etc)
    Alliums should have low and no added Nitrogen soil.
  3. Solanums (potatoes, tomatoes, eggplant)
    Add 0-7-30
  4. Legumes (peas, beans)
    Ideally no N is added; remnants of prior season’s manure is sufficient.

Should there be a fallow year? It’s good practice to leave a fallow cycle, to break cycles of soil disease. But fallow seasons bring issues – nutrients may be washed away, weeds may take over. So fallow ground should be either used to grow green manure such as alalfa (cut before seeding), or comprehensively covered.

More to come on this topic for sure. Meantime it’s useful to read about crop rotation history and practice in this useful article.

Public Enemy Number ONE?

Yesterday I was watering everything as usual and was struck by this sight – dozens of cabbage white butterfly caterpillars slowly but surely intent on destroying my Broccoli crop.! I shook them off, washed off the clusters of black or dark grey eggs and killed as many of the caterpillars as I could find on the ground.

Saw Paul at the gate. He said, “Garlic, only thing to do”. So I prepared a strong mix of garlic liquid and came back down. Sure enough the caterpillars don’t like it; they leap off the leaves to get away. But is that enough I wonder? The root (sic) issue is of course my netting is too coarse grained. I need to change to a finer net that stops cabbage whites getting anywhere near the brassica. The same applies to my cauliflower plants.

This morning they are back, but now in even greater numbers. And they have progressed to several plants. Same process wash them off and kill them. No mercy!

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