Wednesday, 9 April 2008


Now is such a great time here to sow seeds and plants seedlings that I thought I would just recap on what I have found works for me, to get those tiny pinpricks of potential life to burst forth into the world and continue to flourish and provide us with the feeling of satisfaction that comes from picking food from our own gardens. I sow a lot of things using the soil blocker but sowing into foam boxes is equally good, as far as success is concerned. I don't sow into pots (others do, I know) because they get hot and dry out quickly, they can tip over, they take up more space and I try to avoid pricking out (hence the soil blocker preference. Laziness begets invention, I find!) The reason I don't sow into the garden just now is that the garden is still mighty full of the last of the summer things and areas only become free slowly from now on. By the time my seedlings are large enough to plant out, the space will be available. Soil blockers are expensive but we have one in the group and most of the time it lives at my place - I don't know how or why the rest of you do without it!

Getting the seed-raising mix right
If you don't have your own compost or preferred medium at hand then you can combine some bought products: Mix together about equal parts, lets say 4 spades-ful each of bought potting mix and SA Composters bagged compost. Add a handful of blood and bone and 2 handsful of reconstituted coconut fibre. Turn this all through with your hands until evenly mixed. I do all this in an old sink I have at bench height. Now either put the soil into a deep foam box with holes in the bottom and lined with a sheet of newspaper, to a depth of about 10 - 15 cm and water until quite wet but not sloppy or, if using the soil-blocker, add the water in situ. Since my sink has a drain hole it makes it easy not to over-wet the mixture. For the soil blocker to work well the mix needs to be wetter than usual and a bit sloppy is ok.

Sowing the seed in a foam box
Always sow seed into soil that is damp right down to the bottom of the foam box (or at least 15cm when you sow into the ground). So now you have plenty of soil in the foam box but not too much because later you will be placing a sheet of glass or plastic over it and this needs to be well above the height that the seedlings will be so you don't overheat them. Next lightly pat and smooth out the surface. Tip a few seeds into the palm of one hand and with the other pick some up in your fingertips and distribute them reasonably thinly over the surface. Hopefully each one will become a plant so don't put them too thick. Using a coarse kitchen sieve or one made for the purpose, sift some of the compost straight from the bag over the seeds to just cover them completely. Pat down gently over the whole surface.

Water with a misting nozzle. Place a sheet of glass or rigid plastic over the box and put it....difficult to be general here...this time of the year I would put it either in the shade, if its sunny and over 20C or in morning sun or dappled shade if its cloudy or cool. You won't need to water it everyday so long as it is covered. Maybe every 3rd or 4th day water again, lightly, with the misting nozzle. Don't give up - some seeds are quick to germinate and some are slow.

Pricking out
This extraordinarily tedious job is best tackled with some friends, if you have lots of boxes of seedlings to deal with at once. Pricking out means removing each seedling at a very young stage and potting it up into something bigger so it can grow to a size suitable for planting out into the garden. When to prick out is something all gardeners have different opinions about but I would do it once the seedling has its first set of true leaves (ie 4 leaves or so). Using a tool like a thin knife, insert it vertically into the soil close to the seedling and gently lever it out. Immediately place into a small pot of potting mix/good compost (not garden soil) and water in. Leave to recover and grow.

Advantages of the soil blocker
1. No transplant shock - as no pricking out is required - all seedlings are allowed to grow to a size to plant into the garden or the whole soil block can be put into a pot if needs be (like during our heatwave - I potted up all the soil blocks so it was easier to keep them cool and moist).
2. You can make as many or as few as you like at a time.
3. Saves time.
4. A whole row of one type of seed may germinate very fast and this can be removed without affecting the rest.

Growing strong seedlings
I used to find this the hardest part, especially during hot weather, but then I heard a man at one of our meetings say "humidity is everything". I have never seen this man again to thank him for this advice. Once the seedlings are just poking up through the soil they change to living things with at new requirements - sunlight and food, as well as moisture. Put them, still covered in glass or plastic, into a sunny place and then cover them with some white, 50% shade cloth. Rather than taking off the glass, add more shade cloth if it gets hot. This means you are still conserving the moisture in the air and the soil. When they are stronger and the days are cooler, remove all the shadecloth. Prick out and transplant to pots, or leave in the soil blocks. Eventually remove the glass too to harden them off. If this all seems to be taking more than forever, give them a very weak spray with a liquid feed.


Belinda said...

Hi Kate,

I am very interested in soil blockers. Did you make yours or buy it?

I haven't been able to find them over here but I think they are a great idea.

Kind Regards

Maggie said...

Well I just put the seeds straight into the ground, and then thin them out as they grow.
Plus I always buy some seedlings from Diana and Jen.
I put netting over the whole garden or the birds scratch the seedlings.

Kate said...

Belinda, you can get them online from Gundaroo - click on the 'soil blocker' link in this post. We got ours from a local supplier but she got them from Gundaroo anyway.

Chook said...

Thanks for this post Kate. I'm all inspired and off to plant some seeds now. It's about time I got back into it all!

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