I guess, if you asked any gardener how to sow seeds, you would receive a different answer from each one.
I recently gave a zoom presentation to the Worcestershire Careers Association gardening group on seed sowing.
These are my thoughts.
There is a wide range of pots and containers for seed sowing, generally, I prefer to use small pots rather than seed trays because they provide a deeper root run until you get round to pricking out the seedlings.
Large seed trays also encourage the sowing of too much at a time.
I also use root trainers. The large ones are useful for growing sweetpeas, beans and sweet corn, and they save pricking out. You can then plant them directly into the garden. You can buy smaller ones, ideal for starting vegetables such as lettuce or annual flowers.
A free alternative is used toilet rolls centres which fit nicely into the plastic containers grapes are sold in.
The choice of compost can be a controversial area. Legislation regarding the use of peat is driving the move to peat-free compost.
I think you only need one type of compost, multipurpose. I use Melcourt ‘sylva grow’, a peat-free one recommended by the RHS. This year I am experimenting with using Fertile Fibre, a Coir product. This is dehydrated making it light to carry and is easily rehydrated for use.
There is no doubt peat-free compost requires more feed, which may explain why some comparisons show poor results.
I also use fine grade vermiculite for seed sowing, it is light to carry, helps prevent seedlings from damping off and benefits root development. Vermiculite is a naturally occurring mineral that is heat-treated. Traditionally horticultural sand or grit would have been used and as a gardener with recurring back problems, reducing the weight of materials is an important consideration.
For small seeds, I sieve multipurpose compost, to remove the larger pieces, mixing it 50/50 with vermiculite. When planting small seeds, I water from above before sowing or from below afterwards.
After sowing I lightly cover with vermiculite and label. You can cover it with a polythene bag and place it on a well-lit window sill. I use a heated propagator which negates the need to cover individual pots. You will need to remove the individual cover when the seeds have germinated, keep warm with good light to prevent them from becoming leggy.
Coir Jiffy pellets are useful for propagating seeds and cuttings, they require soaking before use.
Once germinated they can be planted out into pots to grow on, this also saves pricking out.
I use a mixture of compost with around 25% vermiculite for growing on.
I grow larger seeds such as sweet peas, broad or runner beans in the same 50/50 mix without sieving, planting into root trainers or toilet roll centres.
What is your secret to successful seed sowing?