Friday, 16 March 2012

Garden Organic Fact-sheet GS1: Growing from seed

Here is an example of a very useful Garden Organic fact-sheet, kindly forwarded by Sara.

Lots of other fact-sheets are available from Garden Organic if you are a member.

Their member’s area is a fantastic mine of information on organic growing see:

        Garden Organic Fact-Sheet GS1:  Growing From Seed

Growing your own plants from seed is easy and very satisfying even on the smallest scale. The sight of green shoots poking through dark compost arouses a feeling of parental pride in almost everybody.

Sowing seeds

There are three ways to start seeds off

directly outside - this is best for root vegetables, and possible for many other vegetables, and should be done when the soil is warm.

inside in pots - this gives a higher success rate, as you can take better care of your plantlets. Plants like tomatoes and courgettes which are damaged by frost can get off to an earlier start if sown inside first.

inside in modules - these only have to be transplanted once when they are transferred outside. This can be very handy if you have a distant allotment when you can get your plants established in the safety of your own back garden.

'Inside' could mean a light place in the house or shed, a conservatory or a greenhouse.

What you will need

Seed modules & paper pots – available from the Organic Gardening catalogue

a light place, not too hot, e.g. a North facing windowsill where your seeds can grow undisturbed

containers - well washed yoghurt pots are fine if you can't find a flowerpot

compost - buy a specially formulated seed compost from the garden centre or Organic Gardening Catalogue. This has been sterilised so what comes up is what you put in

What would you like to grow?

onions, cabbages and fennel are really easy to sow in modules.

tomatoes and marrows do better in pots

lettuce and other salad greens can be sown outside or in modules

peas and beans can be sown outside or in modules

don't bother trying to sow parsnips or carrots in small containers or modules because they hate being disturbed for transplanting

When to sow

Champion onion growers traditionally spend Boxing Day in the greenhouse sowing their best seeds but unless you really feel a need for football sized veg you don`t have to. Most seeds are sown much later! Follow the guidelines on the seed packet or view our website “What to do in the garden now” for a month-by-month guide.

A good time to start growing lettuce seeds on a windowsill inside, in the Midlands, would be early March. If in doubt, look out of the window first and think if you would be happy left outside there! Remember that your veglets will move outside quite soon and you don't want them to get too big before you plant.

How to sow

Seeds vary in size and shape a lot. Some are huge, like avocado seeds, while others are like fine dust such as rhodedendrons. Fortunately vegetable seeds fall between these extremes.

If the seeds are large enough to handle individually, like the little bullets of brassicas, try to space them out evenly around the container. Big seeds like beans can go two or three into a yoghurt pot. Pull out the weakest seedling to let just one live and grow up healthily. As a general rule cover the smaller seeds with as much soil as they are tall. Bigger seeds like peas can be pushed into the soil as far as the first joint of a middle finger.

What to do

1. First, make sure your pots are clean (with holes in the bottom if it didn't start life as a flowerpot.). Check your compost is fine and friable, not too wet or too dry - and not last year's either! Even compost has best before dates and loses nutrients over time. Fill your container up to the top, press down very lightly and give it a tap to settle any air spaces. Using a handy straight edge, knock the top compost off level with the top of your container. Put a little water in a bucket and gently float your container(s) in it. As the compost becomes wet from below they will slowly sink. When the top starts to look wet, fish them out and stand them somewhere they can drain without getting in the way. Plant your seeds in a way appropriate to their size - check the seed packet for details.

2. Carefully stretch clingfilm over the top, or cover with a polythene bag secured with an elastic band. If you have some correctly sized pieces of glass, use these to cover the containers. This means the moisture in the compost won`t be lost from evaporation and you don`t need to water again until the seeds are through. Place the container on a windowsill where it will not have the sun shining directly on it or be right on top of a radiator.

3. In ten days or so, the soil will start to heave upwards and soon you will see the first little green tips of your seedlings forcing their way up to the light. Take off the clingfilm, polythene bag or glass and cautiously feel the compost with a finger. If the top is dry, stick your finger in a bit deeper and see if it feels damp further down. Use fresh tap water on your seedlings as rain water can contain micro organisms that cause “damping-off” - a fungal disease that will make your seedlings keel over and die.

4. As soon as the seedlings are big enough to handle, if there are a lot in your container, move them on into individual pots or trays. Plants hate being overcrowded. If you only want a few plants pull up the weakest seedlings to give the rest some space. Push an old seed label carefully into the soil to loosen it and separate each plantlet by holding it with one leaf, not by the stem. If you have only one seedling in a pot, leave it in there until it has grown about four true leaves. When transplanting seedlings try to plant them down as far as you can, so the lowest leaves are just resting on the soil.

5. Plants grown on a windowsill often get leggy when they are looking for light. Try to remember to turn the container regularly. Seedlings need lots of light so you may need to change windowsills if they get too leggy.

6. As the plants grow, stand them outside on sunny mild days to get the full benefit of light and air. If a mild night is forecast and they seem to be growing well, leave them outside overnight. Gradually harden them off over about a week to ten days, before planting them outside. If a frost seems likely just after your plants have gone into the ground, don`t panic! Covering them with a few sheets of newspaper or a piece of horticultural fleece overnight will be sufficient protection against most spring frosts.

Sowing in modules

1. This method of sowing has become very popular commercially in the last few years. New module trays in various sizes are available from most garden centres but quite often secondhand module trays, which look like little plastic honeycombs, are available from nurseries at very low cost. If you use these make sure they are thoroughly washed and dried in the sun before filling them. The original recyclable module tray is the cardboard eggbox. Tap the seedlings out at planting time and put the soggy cardboard remnants on the compost heap. You can also try using old loo roll middles. Plants can be transplanted directly without removing them from the tubes, as these will rot down naturally in the soil.

2. Fill and water the tray as if you were sowing in a pot. Place a single seed in each pocket or module, and cover very lightly. For the larger seeds use bigger modules. Clingfilm, polythene or glass may help. If you are using a windowsill, the large trays that hold meat in supermarkets come in very useful for standing module trays on, once they have been well cleaned.

3. Watering modules needs more attention than pots - somehow one corner always seems to dry out quicker than the rest.

4. When the seedlings are starting to show several threads of white root at the bottom of their module (through the drainage hole in the case of plastic) it is time to move them out. If you're not sure if it's the right time, tap one out - it should have a network of roots holding the soil together.

5. Hardening off is the same procedure as for pot grown plants, but remember modules dry out quicker, can be more easily damaged by frost or wind and can be light enough to blow away. Modules aren`t difficult but they do need to be watched carefully and perhaps should not be attempted as the first thing you ever grow.

6. As the seedlings suffer less disturbance this way you can sow crops like celery and beetroot which normally resent root damage. Plantlets usually grow away faster provided they are not left in the modules for too long.

Sowing outside

Sowing outside is even easier.

1. Choose a day when you feel happy outside without a coat - this will usually be a fair indication that the soil is warm enough. Make sure that the place you want to sow is free of weeds.

2. Rake the soil gently free of stones and lumpy mud; this is what is called a fine tilth.

3. Some plants need more room than others, so look at the instructions on the packet. Draw a shallow line in the earth with a stick or the edge of a hoe for larger seeds like peas and beans. Beans and peas are often set in a double row so they can support each other as they grow. Mark the top and bottom of your line with a stick so you can find it again!

4. Sowing the seed is the same as in a pot, but sprinkle them lightly and rake over just enough to cover them. If the soil is very dry, water where you are sowing really well, then cover the seeds with dry soil. Peas are usually spaced about a thumb joint apart, broad beans about 8cm/3" apart. French beans go a little wider apart.

5. Look for your seedlings - some will come up fast, like cabbages, and others are very slow, especially parsnips. It is a good idea to sow radish and parsnip seed in the same spot because not only will it remind you where the parsnips are but the radishes will be ready to eat by the time the parsnips are starting to emerge.

6. In very hot weather lettuce seed goes to sleep, so if it hasn't come up, don't worry because it probably will germinate as soon as the weather changes. Your seedlings may need thinning out if they are growing very close together.