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Sowing The options are limited but there’s still time for growing in the greenhouse
THERE’S still time for sowing seed in the greenhouse. As I said last week, I’m itching to start sowing in my new greenhouse and hope for a small crop. So, if you’ve got a spare corner under glass, have a go. Your choice is limited to quick-growing leaf crops such as lettuce, oriental greens, chard and some herbs. These plants need little nutrient, so you could use an old growbag or spent potting compost. Revive the compost with a fertiliser such as pelleted chicken manure or a liquid feed and put the bag in a sunny place. If your greenhouse isn’t frost free, protect pots and containers with extra insulation.
There’s no shortage of fast-growing leaf crops. As well as the lettuce I mentioned last week, I’m sowing some herbs, oriental greens, mustard greens and winter cress. And I couldn’t resist sowing and potting on some chard and parsley a few weeks ago.
You’ll only succeed when you provide the best growing conditions. The sun being weak, you have to capitalise on what light you’ve got. This explains why greenhouses always have single panes of glass. Although the double glazing in conservatories makes them warmer, it lets much less light through and is therefore less beneficial to plants.
Roofing material is also an issue. By reducing light levels in the summer, polycarbonate roofs are ideal because we don’t need shading to protect plants from the scorching sun. But, in winter, glass lets in more precious light.
Although you can increase the strength of the light your plants get, by cleaning and moving them closer to its source, you can’t control the length if the day without grow lamps. And day length may influence when a plant will bolt. For example oriental greens, such as mitsuba and baby pak choi thrive during shorter days and and are only stimulated into bolting by lengthening spring days. So these oriental brassicas make the perfect choice for now.
If you’re put off by the bitterness of some of these greens, try making them more palatable through extra watering. The more you water, the more you dilute the flavour, in this case, bitterness.
Warm soil can also result in milder leaves. Soil-warming cables are fairly inexpensive and cheap to run, so make an excellent investment. You’ll also get much quicker germination and steadier growth. My rocket Esme germinated within a couple of days and is racing away. Some herbs, such as dill and coriander, produce few useful leaves when sown outdoors in autumn. I find you get much better results from a final greenhouse sowing now. It gives us a small crop of decent-sized leaves that aren’t coated with mud.
Seeds also need light to germinate, and because it’s in such short supply they should be covered by the tiniest dusting of soil. And always water before sowing to keep the seed at the right depth.
Treat all the greens as cut and come again, snipping one section of planting to 5cm above ground level. This preserves the growing point and allows the plants to produce another flush of leaves by the time you’ve cut the rest of the crop.
Finally, waste not want not. Check through this year’s old seed packets to see if you can sow any as baby greens. Kail is especially rewarding, with all its different shapes and leaf texture. And peas are fast growers, adding zest to a sandwich when the shoots are cut at 5-7cm.
If your greenhouse is anything like mine, your plants are fighting for every square inch of ground. It also has to be a haven for legions of less hardy and tender specimens. Pack them close to reduce frost damage.