How to Germinate Seeds: Fundamentals for success

Seeds can be sown directly into the ground, which avoids any later transplanting, but often we sow seeds into a container like a punnet.

When seeds are sown in a punnet, it is easier to create the optimal conditions for a seed to germinate.

For great success with seeds consider these three fundamentals for germination success:

1. Moisture
2. Sowing depth
3. Soil temperature

Moisture

All seeds need moisture to start the process of germination.

The seed coat absorbs water, the seed embryo enlarges and - ka boom - out breaks the root (radicle) followed by the shoot (plumule) which develops into the leaf and stem.

The art of seed sowing is to water regularly (1-2 times per day depending on the weather) so the seed never dries out once sown.

Avoid sitting the seed punnet in water as if waterlogged the seed can rot or will not be able to absorb oxygen which both seeds and roots need to develop.

Use your pinkie finger in the corner of a seed punnet. Is it cool and damp below the surface? If so, no watering is needed. When watering, ensure water penetrates from the surface right to the container's base, encouraging those roots downwards.

Misting and spray bottles don't cut it. The surface will look damp, but water will not have been absorbed in the seed raising mix right to the base.

A watering can with a fine rose or bottle top waterer do the trick.

Light and sowing depth

Some seeds will need light, and others will start the germination process without it.

The sowing depth is essential. Use the width of the seed as a rule of thumb. Sow the seed as deep as the length of the seed. So beautiful broad beans will be sown roughly 2 cm deep into the soil, while our finer friends like poppies and lettuce seeds can be sown on top of the soil or seed raising mix and will settle in after a watering.

Minimal if any soil or seed raising mix is required on top.

If seeds are sown too deep into the soil, they may not be able to crack through to the surface with their resources. Let's not make it too hard for them.

It would be best if you were a bit more vigilant on the sowing of finer seeds, as being that bit closer to the surface, it easier for finer seeds to dry out.

The use of a see-through propagation lid or cloche can assist in maintaining moisture levels.

Soil temperature

Seeds have evolved to germinate at particular soil temperatures, summer fruiting and flowering plants, i.e. sunflowers and tomatoes need soil or our seed raising mix a minimum temperature to germinate successfully.

It is less essential for flowers and vegetables, which flower and fruit in cooler months, i.e. sweet peas, poppies, Asian greens, peas etc.

The summer flowering and fruiting seeds need warm soil or seed raising to germinate; about 20-21 degrees celsius is ideal. This warmth can be artificially created with a heat mat which sits underneath seed punnets and radiates heat directly up to the seed raising mix; grandparents have sat seed trays on the top of hot water services in the past, or find other warm locations or make a greenhouse in a well lit warm room or window sill.

As long as the seeds are cosy as we head into spring, germination will improve.

Recycling containers is great, but do clean them thoroughly between uses, so no diseases hang about.

Punnets are like nurseries for our plant babies, so keep containers clean before sowing.

Good quality seed raising mix is important, or make your own with a fine texture, which holds moisture and is free draining.

A blend of worm castings, fine coir and sand can work but clean the sand first (even bake it in the oven to remove any cheeky weed seeds).