Hi i have started to farm worms and I have some castings could you give me a few tips on making a seed starter with castings?
Hi Andrew, thanks for the question.
As a general rule, the amount of VC in a seed raising mix, or any potting media, should be no more than 20%. The best “bang for your buck” is between 15 and 20%.
This is because extra VC will actually make the properties of the media worse – weird, I know. But it makes the media water repellent and reduces the amount of air in the media (air filled porosity).
So, use a decent seed raising mix from somewhere – and give it the extra legs with some VC. Mix 4 parts media with one part VC (giving 20% VC)
You may want to sieve your VC, if you have not done so already, so only the “fines” go in the seed mix. It’s not imperative, but it may help it mix into the media better.
If you want to mix it up from scratch, at Horticulture college I used this mix with a lot of success:
9 parts coco
3 parts perlite
2 parts VC
This results in 14.3% VC (by volume).
More info on using VC etc is available on my site at:
Good luck with it – and again, thanks for asking your question.