I’m now three weeks into my homemade seed compost trial, so I reckoned the time had come to offer up some thoughts.
Firstly, as satisfying jobs go, they don’t come any better than sieving your own potting compost. I’ve been using equal part kitchen compost, leaf mould and molehill soil for my mix, and the beautiful, soft soil that results from half an hour of sieving is a delight both to eyes and touch.
I’ve got an old florist bucket that I’ve marked halfway with a permanent marker and when I’ve got compost to make, I fill this up each time, kick back in the sun, and rub the ingredients through my sieve.
Little and Often Production Line
However, too long at a sieve can send a man doolally, so In terms of production, I’m going for a little and often approach.. The half florist bucket measurements provide me with enough compost for about 15 13cm pots, so a quick sieve once a week should keep in enough compost for this trial.
I’m trying bigger, more powerful seeds in my own compost. These are more identifiable when germinating, and strong enough to not get narked off by the weeds which ultimately come through.
Using unsterilized, homemade soil, weeds are unavoidable but they’ve certainly not taken control. Each pot has required no more than a gentle pricking out of infant weeds once a week, which is a small price to pay for free compost and the satisfaction of making it yourself.
I have sowed French beans, runner beans, broad beans, and some courgette seeds in my own compost over the past few weeks, and all have germinated and are growing on well. I’ve also potted on chilli plants in my own compost, and these have probably provided the most random weed invader:
I’ve also sown my squash seeds into homemade compost over the last week, and I eagerly await signs of germination. Now I’m over the initial anxiety of using my own compost, I’m more confident in its abilities to nurture a more delicate seedling so will extend the experiment to other veg in the weeks to come, such as cucumbers.
Rapid Dry Out
The only real downside to making my own compost is the speed in which it dries out. The greenhouse is very warm at the moment, but I have to water the pots every day, which is not the case with shop-bought equivalent.
I am surprised by this, as the soil seems very moist when freshly sieved, and stays so when stored in a bucket. The molehill soil is clay-based, so I thought water retention would be good.
As an aside, clay also holds nutrients well, so this will definitely help any seedlings that come up and establish themselves in the soil.
My current after-the-sun-sets-job is researching options for helping retain moisture in my soil and preferably natural or organic ones. I’ve been recommended GroChar on Twitter, which I’ll be checking out, but if anyone has any free or cheaper natural suggestions I’d be delighted to hear them.