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"Close the loop, adapt your plants, increase diversity,
resist the monocult."

NB: This text concentrates on the practical side of seed saving; try why save seed? in the seed zone for more information on the issues involved.

r e c o r d s    &    l a b e l l i n g

Keeping good records of your seed saving activities is essential. As well as a marker in the ground, each variety should have a file recording seed details such as the name/s, source, last planting date, last germination rate and the accession number. Notes on the plants themselves can include germination and planting times, time to maturity, fruiting season and productivity, the size, shape, colour and flavour of fruits and any notes on soil, pests, diseases or other growing conditions. Keep a record of the weather, especially unusual events, as it may significantly effect the outcome of plants grown from year to year and is always good to check back on.

Try to adopt regular habits, such as marking rows out before hand and always planting from back to front, left to right. This will reduce the chance of muddling varieties, double planting rows and other such mistakes. If you get distracted you’ll know where to begin again.

This said, only record important stuff, and don’t loose your spontaneity. Otherwise you’ll end up writing and planning more than growing and enjoying.

p l a n t i n g

Plant everywhere!

You don’t need some regimented row, just some (relatively) spare earth and a bit of time. My T-shirt says "Plant plants then plant some more;" with that in mind, grow things wherever you can but remember….

Plant more

If you are intending to save seed, grow more plants than you think you need, this allows a margin of safety for the unexpected and ensures there will be enough true-to-type plants to take seeds from.

Allow more space

Saving seed requires you to grow plants to maturity and consequently they get bigger and stay around longer than normal, so leave a bit more space around them. You may also need to clear space in your head to let ideas of garden ‘tidiness’ go. The plants you choose to go to seed will likely be scattered in your bed so you have to be flexible in your design and later plantings.

Plan for isolation

By planning your garden, so similar outbreeding plants are as far apart as possible, physically or in time, you maximise the chance of maintaining the variety. Look up recommended isolation distances or choose early and late varieties that flower at different times. Remember to check with your neighbours who might be growing something that’ll cross, if it’s a similar variety - mechanically isolate yours, if it’s GMOs tell them to stop!

s e l e c t i o n

Pick the right plant!

Plants, as living things, are constantly adapting to their surroundings. Saving and growing seed, year on year, is taking part in evolution. You can increase the chances of this being more useful to you, by bearing a few things in mind.

Recognising the genetic diversity within a variety is the key to realising that each year some plants will do better than others. Environmental factors such as season length, rainfall, frost, nutrients, pests, diseases or genetic mutations effect which plants are most ‘successful’. However, ‘success’ is a word that you, as the seed selector, define. For inbreeding crops you just choose which to save seed from, with outbreeders you may also have to rogue out some plants before they flower.

By choosing plants with particular characteristics to develop seed from, you increase the likelihood of next years crop being similar. As with many opportunities, this is a double-edged sword, if you make an incorrect choice you can lose valuable traits, rather than gaining them. Don’t just plumb for the biggest plant or seed without first evaluating other factors such as the taste, colour, cold, drought, pest & disease resistance, crop yield (do you want 2 big fruit or 10 smaller ones?), harvest season (all at once or spread out?, early or late harvest?), storage qualities, vigour, hardiness, trueness to type and even the quality of the soil around that particular plant. Don’t pick diseased plants if you can help it.
Stay in a wholisitc frame of mind and consider the whole plant, but in the end don’t be afraid of choosing, vegetables today got to be how they are this way.

If you like the idea of consciously taking part in a plants evolution there are several, more involved plant breeding techniques you can get into.

Number of plants

The number of plants that you save seed from can be critical to maintaining a variety, depending on the breeding tendencies of the plant. Seeds collected from too few plants will not represent the full genetic diversity of the variety, which in many cases will be lost. With open pollinated varieties it is good to try and save similar quantities of seed from as many ‘true-to-type’ plants as possible, then mix them well. If true to type means a large variability, save seeds from widely different plants! Most self pollinated plants are naturally inbred, and can stand being saved from just a few plants from year to year. Look up information on individual plants for details of the minimum number of plants you should grow. Once you’ve chosen make sure they are very well marked, it only takes a few hungry people to inadvertently ruin your seed harvest.

i s o l a t i o n

Although you can separate plants in distance and time, this doesn’t always work out. Often, lots of nearby gardens mean a large diversity of plants are grown in a relatively small area. Although wind and insects won’t carry pollen as far in built up areas as over open land, the chances of cross pollination from unknown plants nearby are increased. So in urban areas or allotments it is often safer to mechanically isolate your plants, you can do this in several ways.


is the simplest method and involves covering the flower heads to keep out pollen. Use breathable material such as Reemay or a paper bag (watch out for rain!) Secure snugly around the stem or insects will crawl in, (you may need to wrap the stem with cotton wool first.) After flowering the bags are removed and the fruit marked for seed collection with string.


is used to cover entire plants, and prevents outside pollen reaching any of the plants inside. It is good for plants that flower over an extended period of time, so you don’t have to keep bagging flowers as they open. Self pollinating species can be left to get on with it whilst outbreeders need to be hand pollinated. Cages consist of a frame covered with Reemay, nylon mesh or net curtain. Use whatever structure you prefer, hooped tunnels are probably the easiest to make and use on rows, rectangular cages easiest to move. Make sure there are no gaps between the soil and bottom of the frame.

Alternate day caging

is used to grow similar outbreeding varieties, that would normally cross with each other, in close proximity. A cage is put over each variety when flowering begins. Each morning one cage is removed to allow insect pollination, then returned at night when there are no insects about. This is repeated, in rotation between all cages, until flowering stops. The method can be used on up to four varieties but will reduce pollination and thus seed production significantly as more cages are used.

p o l l i n a t i o n

Self & Cross pollinators

Plants either self pollinate or need an intermediary to transport pollen from one flower to the next. This makes a big difference to how you go about saving their seed. Self-pollinators are often inbreeding and have perfect flowers which fertilise themselves. Cross-breeding plants outbreed to various degrees and have either imperfect flowers or self- incompatible perfect flowers which need to be pollinated via insects, the wind or you. In a garden most self and all cross-pollinators should be isolated from other varieties in their species, or be hand-pollinated, to ensure varietal purity. Roaming insects pay little attention to human classifications.

Hand pollination

This sometimes laborious method involves the hand transfer of pure pollen from the stamen of one flower to the ‘virgin’ stigma of another. It is used when you want to be as sure as you can be that your seeds are pure. Male and female flowers are protected from insects before they first open and when they have developed, watching for stray insects, they are unsealed and pollen is transferred with the stamen itself or a fine paintbrush. The female flower is then protected in some way from contamination by other ‘foreign’ pollen. Methods vary for individual plants.

Harvest & Preparation

Harvesting seeds is a matter of leaving them to develop as long as possible without losing them to the elements, pests, or someones’ stomach. It is good to leave the seed body on the plant longer than if you were going to eat it, especially for those plants which are eaten immature. For ‘wet’ plants harvest as you would to eat, then leave inside for a while for the seeds to finish maturing. For seeds that dry on the plant, try to harvest on a dry day and if bad weather or frost looms, pull the entire plant and bring it inside to ripen. Methods vary for individual plants.

Wet cleaning

Seeds that come within a ‘wet’ body should be washed in water until all flesh is removed, then placed in a warm place on a plate or paper strip to dry naturally. Some plants such as tomatoes need to be fermented first, to remove a coating that inhibits germination. To do this, put the mashed fruit in a jar, leave no longer than 4 days in a warm place until a crust forms then wash and dry as normal.

t h r e s h i n g    a n d    s e p a r a t i o n

Seeds harvested from a dry plant should be threshed. This involves gently crushing the seed cases to break them free of the seed, put larger seeds in a pillow case and tread on it, smaller seeds can be crushed between two bits of board. Don’t apply too much pressure or you’ll damage the seeds. The chaff is then separated from the seeds by :

winnowing – tossing the seeds in the air in a breeze that blows the chaff away. This is good if you have lots of seed and a constant light breeze, use a sheet on the ground to rescue seed that gets blown away.

blowing – to blow the chaff off the top of a bowl of seed, this is good for small quantities, denser seeds go to the bottom, leaving the chaff on top. Use a modified hairdryer, or reversed vacuum cleaner.

sieving – using various graded screens that let only the seed or chaff fall through.

Insects and diseases

A ‘hot water treatment’ can be given to certain seeds such as cabbage, turnip or tomato, (look up individual plants) to kill off diseases they might be carrying. Immerse in water held at a constant temperature of 50° C for 25 minutes. An electric frying pan is best for this, if you can’t find one practice first without the seeds, or you may boil them to death!

Small grubs, hidden inside the seed shells themselves, can be killed by freezing the seed for a couple of days, but only after it has been properly dried.


Proper drying is essential if you want your seed to last. The temperature should always be kept below 35 C and good airflow is more important. Spread them out on trays or screens in warm spots, stirring occasionally. Alternatively put the dry to the touch seed in a airtight jar with an equal quantity of silica gel, leave for a week, then store as normal. Dry seed will not bend and will not dent when you try and bite it.

s t o r a g e

The best place for a seed is growing in the ground. This not always being possible, the things to get right are…


Most vegetable seeds store well at a constant temperature of around 5° C, put them in a cellar or fridge. For long term storage a freezer is best. When you take them out allow them to return to room temperature before you open their container or water will condense on the cold seeds and activate them.


The drier the better. Moisture encourages life, the seeds will slowly loose nutrients and vigour until they die or rot. If seeds are frozen, excess water will rupture cell walls and kill them. Pack seeds on a dry day if possible, putting silica gel or bone-dry grains in the bottom of the container separated from the seeds by some cotton wool.


We put each batch of seeds, with a note containing their essential details, in a small paper bag or envelope. Several of these are then put into an airtight jar and stored in a cool, dark place. Airtight jar seals can be easily made with a piece of innertube rubber.

As you would expect, different seeds store for varying periods of time. In general the bigger the seed and the thicker its skin the longer it will last. Look up specific seeds individually or in this chart.

g e r m i n a t i o n    t e s t i n g

If you are saving seeds for longer than year to year you should do periodical testing to check their viability.

The method

Lay out up to 100 seeds (more seeds = better accuracy), on damp cloth or tissue paper in a regular grid pattern (to aid counting). Cover with another sheet, carefully roll it all up and place inside something that will retain the moisture whilst letting in some air, a plastic bag with a few holes usually works. You should then store the seeds at a constant temperature of around 24 ° C, making sure to keep them moist. A warm box, airing cupboard or high shelf are good places to try. After a week , count and remove the sprouting seeds. Return the seeds to their warm spot and work out the germination rate (the percentage of seeds that germinate out of the total tested). If after another week there are no more sprouts, you can be fairly certain you’ve got it right. But try to find out the germination requirements for seeds you have little experience of, before discarding a test (and the seeds) as a failure.

The results

Bear in mind that the germination rate doesn’t show the vigour of a plant, which may sprout in a warm tissue but find it hard to grow to maturity outside. As plant with low life force is more prone to mutation and disease. If you get a germination rate below 80% you should consider replanting. Rates below 50% demand immediate action.

s p e c i f i c    p l a n t s

Amaranth, Artichoke, Asparagus, Aubergine, Basil, Beetroot, Borage, Broad bean, Broccoli, Brussels sprouts, Cabbage, Carrot, Cauliflower, Celeriac, Celery, Chervil, Chives, Corn, Corn salad, Cucumber, Dill, Endive, French Bean, Garlic, Garlic Chives, Jerusalem Artichoke, Kale, Kohlrabi, Leek, Lettuce, Melon, Mustard, Mustard Greens, Onion, Parsley, Parsnip, Pea, Pepper, Potato, Pumpkin, Radish, Rhubarb, Rocket, Runner bean, Salsify, Soya bean, Spinach, Squash, Sunflower, Tomato, Tree Onion, Turnip, Watercress, Watermelon, Welsh Onion

m o r e    i n f o

Get these books!

The seed savers handbook
Seed to seed



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