Seed raising mix
Want to sow seeds in pots? What do you need? Seed raising mix? Guess again!
Working part-time in the garden nursery industry, I meet many gardeners who have had problems sowing seeds in seed raising mix – they find that their seeds sprout but their seedlings only reach a very small size and then completely STOP GROWING, and the resultant seedlings are very thin and spindly!
That’s because seed raising mix has absolutely no nutrients in it, and is totally unsuitable for growing seeds in. It’s actually misnamed, it really should be called SEED COVERING MIX or SEED GERMINATION MIX, because that’s what it’s designed for, and does well.
What is Seed Raising Mix?
Typical seed raising mix contains Composted Bark, Crushed Quartz, Trace Elements and Wetting Agent.
The composted pine bark in seed raising mix is of a fine consistency, allowing seedlings to push through easily to come to the surface, and to push their roots down also, without any obstruction from chunky pieces of composted bark you find in regular potting mix which would get in the way.
Composted pine bark is the main ingredient in all potting mixes, and is the component in the mix which holds water. The crushed quartz improves drainage, preventing rotting of seeds and fungal diseases in seedlings. Together these two ingredients achieve ideal moisture retention.
Seed raising mix works well for rapid germination of seeds and encourages strong root development, and that it does well, but it can’t grow plants!
Using Seed Raising Mix Correctly
For seedlings to grow to the point where they are large enough to transplant, you need a nutrient-rich mix, which seed raising mix is not.
So, how do we raise seedlings using seed raising mix?
- Fill the seedling tray with a quality potting mix (which will contain nutrients) that has been sifted to take the coarsest particles out, or use a fairly fine grade potting mix.
- Place seed on soil surface and gently press so seed is level with the surface.
- Cover with a layer of seed raising mix equal to the height of the seed.
If you want to use straight seed raising mix (because you bought a huge bag of it), mix it with a nutrient source such as worm castings or a very small amount of well composted cow manure, or both. If your seedlings germinate AND grow, you know you’ve got the right blend!
Want to sow seeds in pots? What do you need? Seed raising mix? Guess again! Working part-time in the garden nursery industry, I meet many gardeners who have had problems sowing seeds in seed raising mix – they find that their seeds sprout but their seedlings only reach a very small size and then completely…
Seed raising mix
Sowing seeds is the most economical way of growing our own food and if all goes well the rewards are both tasty and nutritious. Seeds are often tiny and the plants that grow from them begin life as nothing more than a shoot and a pair of leaves. These small beginnings to our fruit and vegetable plants need a good start if they are to grow strong and become productive. Often we sow directly into our garden soil – which is always preferable – but there are times when seeds have to be started off in trays and punnets. Starting seeds off in the right growing medium is crucial to their ongoing success and so we use seed raising mix. Once these seeds have germinated and produced several pairs of leaves the resulting seedlings can need to be transplanted and grown on in larger pots until they are ready for the garden – as is the case with tomatoes, aubergines and early crops of cucumbers and capsicums. When seedlings are grown into young plants in this way, they are planting into potting mix. Commercially made seed raising and potting mixes are sterile and weed free so seeds and seedlings can develop un-hindered.
Seed raising mix is a gritty mixture of soil particles, organic material and fine drainage components. These are combined into a growing medium that allows adequate drainage, holds onto moisture and at the same time stays open so that delicate roots can move easily through it.
Potting mix has a larger proportion of organic material than seed raising mix. It holds onto more moisture and has higher nutrient levels to sustain developing young plants. It is fairly light and compacts down if handled too heavily. Particles are still fairly small so that young roots can easily find their way through it.
It is useful to havea bag of seed raising and potting mix to hand at all times. There is always a bit of a rush in late winter and early spring when sowing seeds and transplanting are happening in earnest.
Keep bags of seed raising and potting mix in a dry place so that they stay dry don’t get soaked. Not so easy to use when damp.
Application seed raising and potting mix are added to trays, punnets and pots. They don’t usually need any extra drainage material. Handle gently and try not to over-compress them as this can make it hard for delicate roots to spread within them. You may end up with stunted seedlings as a result. Often just pouring your mix into the designated container and then gently shaking from side to side causes seed raising and potting mix to settle enough for sowing and planting.
Seed raising mix Sowing seeds is the most economical way of growing our own food and if all goes well the rewards are both tasty and nutritious. Seeds are often tiny and the plants that grow from