An introduction to microgreens and seed sprouting, Part 3.
October 1 - I now have my vermiculite, a 500ml bottle of organic seaweed fertiliser, which will probably last for ever, a batch of seed labels, so I don’t forget what I’ve sown (not a problem right now, but it may be later), and a write-on-anything pen, for the labels, the type of thing you use on CDs. All from here. Prompt, next-day service, at the seemingly universal rate of £6.95.
Having little idea how much vermiculite is compressed when packed, I bought 10 litres, which has filled all three trays with plenty left over.
CAUTION! If you have any sort of respiratory problem, use a face mask when handling vermiculite, or do it quickly and hold your breath, it’s quite dusty. Some sources recommend wearing gloves, too, but I think that’s overkill - I didn’t bother - just wash your hands afterwards.
I’ve not used vermiculite on its own as growing medium before, as back in the days when I had a greenhouse I’d mix it 50-50 with potting compost, so I’m not sure how it will behave. The first job, then, after filling the trays, was to thoroughly wet the vermiculite. The propagator has a capillary pad in the base which absorbs water and feeds it to the trays.
So all the trays are well wetted, as is the capillary mat, and any excess poured off. What I want to see now is how quickly it dries out so that, once it’s planted up, I’ll have an idea how often it needs watering. There’s lots of info online about growing the seeds, but nothing about the preparation.
To my mind, although it’s labelled “fine”, the vermiculite is pretty coarse, so I’ll blitz what’s left in the food processor (it won’t harm it, it’s quite soft), until it really is fine, and use that as a top-dressing for seeds that need to be covered.
Later today I'll get my seeds sown in the propagator, and put the hemp seeds in soak (seeds for sprouting need soaking first), and see how thing turn out.
The fertiliser, incidentally, is recommended for micro-greens as they’re grown just a little beyond what the nutrients in the seed can support - it won’t be needed until beyond the cotyledon (the very first "seed leaves"), stage. They’ll still grow without it - they’ll grow better with it.
Looking at my set-up (photos when I have some plants to show), I think it might be feasible to grow some of the lower-growing lettuces way beyond the micro stage, especially in the summer, but that’s for next year. Over the course of the winter, I’m going to see if I can get a work-top offcut which, just sat on top of the chest of drawers, would double my growing space.
Right, watering. Whatever you grow will need water, and I discovered long ago that plants, especially seedlings, do best with water at the ambient temperature, not straight from the tap. In my greenhouse I kept a 10 gallon polypin of water under the staging. This had the dual feature of providing water at the same temperature as the growing plants and, during the day, it stored a useful amount of heat which it gave up during the night. For my seeds, though, I’ll use a 2-litre Coke bottle (take care - the plastic is very thin, making it difficult to handle if it's full), with a bottle-top waterer, from Lakeland, which come in a pack of four, 2 fine, 1 medium, and a squirter. The latter is handy for injecting water into the vermiculite to avoid squashing very small seedlings; once they've grown on a little, the fine rose is, er, fine...
Note: A polypin is a polyethylene beer cask - I made my own in those days.
And that’s it for the time being - more as and when…
Update:- October 8 and my first crops of microgreens and sprouts are under way. I sowed the large seed tray in the propagator with alfalfa, and the two small ones with mustard and broccoli. I also have two trays of the sprouter filled with hemp seed.
Two things have become apparent. First, and most serious, my sprouting hemp seeds stink of fish. No idea why this should be, but I suspect I would have been better planting them in the propagator. Still, I'll let it grow and see what the sprouts taste like when they're ready.
The other thing is that published growing times are hopelessly inaccurate. Everything I've planted should have reached the sprout stage at 6 days. OK, the broccoli and mustard have, and are growing on well, but the hemp and alfalfa are very tardy, the alfalfa only now beginning to grow, while the hemp is sowing only a few signs of life