Use seed raising mix as potting mix by adding a slow release fertilizer like pelleted chicken manure. Fix seed raising by mixing through this secret ingredient because most seed raising mix has no added fertilizer so plants won’t grow well for longer than around 6 weeks. Use improved seed raising mix in raised garden beds, compost or worm farms.
Seedlings need to be transplanted from seed raising mix after they grow their second set of leaves.
Difference between seed raising mix and potting mix
The differences between seed raising mix and potting mix are the size of the particles in the mixes and the addition of fertilizer.
|Seed raising mix
|Larger particles, and can also have
|No fertilizer added.
|Added slow release fertilizer.
|No soil conditioners.
|Wetting agents, seaweed fertilizer or fish emulsion extract.
Seed raising mix is finer than potting mix
Seed raising mix is finer than potting mix, It contains a mix of sand and organic matter which allows the seeds to growth through easily. Larger particles of bark or organic matter have been sifted out of seed raising mix making sure that they won’t block the seeds from sprouting through the soil surface.
Fine seeds can struggle to sprout through the larger particles in regular potting mix which makes seed raising mix the perfect starter for all seeds including fruit, vegetables & flowers.
Using seed raising mix in raised garden beds
Seed raising mix can be used in raised garden beds to sprinkle on top of newly planted seeds. Some vegetables prefer to be directly sown into garden beds. Sprinkle seeds on top of your prepared vegetable garden bed and use the seed raising mix to add to the top. You can then water the seeds in.
Seeds like peas, beans, lettuce, Asian greens, onions, carrots, beetroot and radishes all like to be directly sown into garden soil. Simply sprinkle fine seeds like carrot and lettuce on top of raked soil and top off with seed raising mix. This will allow the seeds to be covered and protected but will allow them to sprout through the thin layer of seed raising mix.
How long seed raising mix supports plant growth
Seed raising mix is designed to support the seed to grow around the time of growing their second set of leaves. Most seeds will sprout with 2 leaves to start with and soon grow two more. Once these have grown the seed would have used up all the nutrients stored inside it and your seedling will be looking for more.
To allow them to grow for longer in the seed raising mix, water on a liquid fertilizer like fish emulsion to provide more nutrients. You can also plant them out into your garden beds which have been prepared with a pelleted chicken manure or aged cow manure. Seed raising mix is designed to support your seeds in their first few weeks of growth.
Do you need seed raising mix to grow seeds?
You don’t need seed raising mix to grow seeds in but it does offer some advantages over regular potting soil. It is ready made to sprout seeds so is sifted with the right balance of sand and organic matter to support seed growth.
You can use a regular potting mix to sprout seeds but it will work best if you sift it first. Most potting mixes will contain large pieces of bark which can block seed growth. Make a simple sieve for your potting mix using some timber and some wire mesh. This will remove the bigger pieces of bark making the potting soil better for seed raising.
You can also use coconut coir mixed with worm compost as a great seed starter. Add ¾ coconut coir and ¼ worm castings together in a bucket and mix together. This is also a great mix for starting seeds.
What to do with leftover seed raising mix
If you have planted all of your seeds and have some leftover seed raising mix you can seal the bag over with tape to use another day. If you are keen to use it up, then mix through a handful of pelleted chicken manure, compost or worm castings if you have it. Once you have boosted the seed raising mix here are some ideas for using it up.
1. Sprinkle seed raising mix around the root zones of plants
This will add extra nutrients and water holding capacity. Move the mulch back first and remember to move it back over the seed raising mix when you are done. This can be used around citrus trees, annual flowers, trees and shrubs.
2. Use seed raising mix in in pots for annual flowers or herbs
Once you have added extra goodness in the form of a slow release fertilizer like pelleted chicken manure, you can use it like a regular potting mix. It will work well for annuals and herbs particularly if you are planning to replace them at the end of the season.
3. Add seed raising mix to your compost
Add seed raising mix to your compost heap and mix it through. The added organic matter will be worked through your compost by worms and will incorporate the nutrients.
4. Add seed raising mix to your worm farm
Add extra seed raising mix to the top of your worm farm. You can use it to cover fruit and vegetable scraps to deter ants and to absorb any extra moisture. It can even be used as worm bedding when you are setting up your worm farm.
Seed raising mix is a good idea if you are serious about raising seeds and want an easy grab option that is ready made and ready to go. You can buy it in small and large bags from your garden center or Amazon so if you are a regular seed planter then it is always handy to have a bag at home.
Seed raising mix as potting soil – FAQ
Seed raising mix can be used as potting soil if you mix it with additional slow release fertilizer and compost. Seed raising mix on its own will not sustain long term plant growth so need to be improved before you use it for mature plants. Add seed raising mix to your compost bin or worm farm as the perfect worm farm bedding or compost carbon base.
Seed raising mix will have smaller particles, usually no slow release fertilizer and is often bought in smaller packs. It is ready made to grow seeds until they grow their second set of leaves. Seedlings will need additional fertilizer or will need to be planted out into garden beds. Potting soil will have larger particles and good quality soil will contain slow release fertilizer and soil conditioners like seaweed.
Seed raising mix will not work well if re-used as it will have lost a lot of its structure and can become compact. After you have used seed raising mix then it can be added to your compost bin or worm farm as worm bedding. Old seed raising mix left in open bags can dry out quickly and become hydrophobic. The best way to use seed raising mix is to buy it fresh and use it all.
Seed raising mixes make the perfect starter for seeds as it is specially made to contain fine particles which will allow seeds to grow through it easily. It will contain fine sand particles which will allow water to drain through and avoid rotting the seed.
Seed raising mix as potting soil – Summary
Seed raising mix can be transformed into a fantastic soil to grow your plants if you top it up with extra fertilizer and compost.
Leftover seed raising mix can be used in raised garden beds, compost or worm farms. Just remember to add some extra slow release fertilizer first.
I am an accredited practicing dietitian, experienced gardener and a dedicated cook. I love writing and sharing my experience so you can learn from my successes and mistakes.