How to Sow Seeds

Basic Rules of Seed Sowing

The majority of seeds are normal germinators especially annuals and many perennials (There are exceptions ..see below) and if the following rules are followed germination should be successful.
1. Clean all containers well. Use clean water to water seed trays.
2. Use a general peat or soil based compost, which does not consist of too fine a material as drainage and aeration are important.
3. Fill trays or pots to half inch below rim. Flatten out surface, but do not firm compost down too hard or this will lead to waterlogging.
4. Dampen but do not wet too much the compost in the seed tray.A watering can with a very fine rose is essential. Later too much force of water from a coarse rose will wash the seeds into the sides of the trays. Sow seeds thinly and evenly over surface of compost. 300 seeds is more than enough to a standard sized seed tray. Gently spread a layer of vermiculite over the seeds until you can no longer see the compost surface. Fine seeds need very little vermiculite, larger seeds will need more. eg. Lupins will need 1/4 to 1/2"
5.Place the seed tray in a warm place, 18oC, and do not cover with glass or plastic. Bottom heat is best from a propagator. Keep an eye on the trays and check that they are damp by feeling how heavy they are. Water them when they are starting to become light in weight showing that they are drying out. Too much watering is the main cause of seedlings dying.
6. Some seeds are so small that it is best not to cover them with vermiculite. Lobelia will be best sown on the surface and will then need a layer of glass placed over the container to stop the seeds drying.
For all seeds it is best not to cover them with compost which is fibrous or has large particles. What will happen here is that the germinating seedlings will lift the full layer of peat covering them. They will never reach the light and will die.

Seeds with special requirements

Many seeds have special requirements and it is best to check in a good seed catalogue that the seeds you are sowing are not amongst them.
1. Lupins and other seeds with a hard shiny coating may need to be scatched on sandpaper to allow water into the seed.
2. Lettuce and pansies will not germinate at high temperatures ie. above 60oF.
3. Alpines and other plants from cold regions may need a period of freezing and cold weather before they will germinate. Aconitum, trollius and many primulas are included here.
4. Delphiniums, aconitums and others require darkness to germinate.
5. Some species require periods of cold temperatures and may take longer than one year to germinate. These include androsace, hellebores, soldanella and many others (often alpines).
6. Some irregular germinators including kniphofia, astrantia,physalis, scabious etc don't have any regular patterns of germination. Some of the seeds of one species may germinate at once whereas others may not germinate for many years. It is necessary to retain the seed trays for a good period of time.
Germination of many perennials will be better with fresh seed or with seed that has been stored well over the winter ie. in sealed containers in a fridge(not a freezer)
I have yet to get hellebore seeds to germinate in seed trays, yet they will often come up like weeds if the seeds fall into a layer of chippings in the garden.

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Last updated Jan 2001