After the cold start to the year – the snow, the wind, the minus temperatures and the frosts – most of us are probably more than a tad behind schedule.
In some respects, that’s no bad thing. Come the start of the gardening year, we’re all feeling a bit ‘stir crazy’ or suffering from cabin fever, having spent most of the winter indoors, and desperate to start sowing and growing everything we can lay our hands on in a blur of activity. And we usually start sowing too early as a result. But if we can’t provide the right conditions for good germination and sturdy plant growth, it’s a good idea to sit back, chill out a bit and delay things. Don’t worry, there’s still plenty of time to spring into action.
Outside, most spring-sown seeds won’t germinate until the soil temperature reaches a minimum of 7C (45F); it’s important to understand that that’s soil temperature! Instead, they’ll just sit there and rot. A few years ago, after a cold winter, I sowed some grass seed over the Easter weekend to repair gaps in my lawn. Ten days go by and nothing had germinated. After scratching my head for a wee while, I decided to test the soil temperature – 2C (35F), far too low for grass seed to germinate, which is usually at 4-5C (40-41F)! I had to wait a week and start all over again.
If your soil is still too cold to sow seeds outdoors, especially veg seeds, then you can warm it up first. Cover it with cloches or, better (and cheaper) still, sheets of clear polythene for around a week – or more if necessary; don’t use black, as this will actually cool the soil, rather than warm it. The other great advantage of using clear polythene is that it encourages all the weed seeds in the top of the soil to germinate, and the soil underneath soon becomes clothed in a carpet of green weed growth. Remove the polythene and then hoe the weeds off and put the cover back. If more weeds grow, repeat the process. This then means that when you’re ready to sow, the vast majority of weed seeds in the top layer of your soil will have already germinated, giving you weed-free growing conditions for your plants’ start to life.
Or just cheat!
Or to cheat on time, you can sow your veg seeds in small pots or cell trays and place them in a cool greenhouse or growing frame. This will give you a head start and lots of young plants that can be planted outside when they’ve developed a good root system and the weather has warmed up and they’ll get off to a flying start.
If you want to make sure you have salads and other crops ready to eat for as long as possible and do away with the famine and glut cycle, keep sowing indoors every two weeks and then plant out as other crops go over and you have gaps to plant into.
Indoors, the issue isn’t usually warmth – but light. Early in the year, light levels – even on a windowsill – can be too low for strong, healthy plant growth. This leads to elongated, thin, weak seedlings that bend awkwardly towards the light. The plants are usually useless and only worthy of composting. As we get further into spring, light levels improve significantly and plants do so much better too.
If you want to make the most of any light on the windowsill, try making a light box. Get a cardboard box, and cut off the lid and the front, then line the insides with aluminium kitchen foil. This reflects light back onto the plants, making conditions much better for good growth.