Avid gardener Nick Harman explains why April is the best time to start sowing vegetable seeds in the back garden and why windowsills are perfect for growing herbs.
The average wait time for a London allotment is five years and in Camden it’s said to be an incredible forty years; by the time you got a plot there you’d have difficulty walking to it unaided. This supply failing to meet demand situation is due to the growing number of young people who want to grow their own vegetables, but also by allotment land being grabbed to build flats. But even if you only have a small patch of land out back, you can still plan to plant edible enjoyment – and April is the time when it all kicks off.
First things first – get your bit of arable land ready. My advice for small spaces is to build a square box of wide planks nailed together. Don’t go too large; you want to be able to reach right to the middle without having to ever walk on the soil, because compressing soil is bad. One sturdy box will do, but if you have space build as many as you like.
Stand your box level on the garden earth, which you’ve already worked over to loosen up a bit, and then fill to the top with a mix of good compost and quality soil, both purchased from your friendly neighbourhood garden centre. Using a box means all that good stuff will stay in one place and each year you can top it up as it slowly sinks.
Many people, myself included, get a bit carried away in April, as the first rays of sunshine arrive and we start germinating too much, too soon. What you don’t want are windowsills full of small plants that can’t go out because it’s too nippy at night, so chill out a bit on the sowing. At the moment I’m only growing tomatoes and herbs in small pots of multi-purpose seed compost indoors.
On the subject of seeds, Lidl have a great selection at this time of year and we’re talking prices as low as 29p a packet as opposed to over £2 from the big name seed companies. Lidl tomato seeds have proved winners for me year after year, with high yields that are resistant to disease.
A top tip for starting tomatoes indoors is to put a freezer bag over the pot; this creates a cosy humid atmosphere and encourages germination. Remove the bag when the seedlings appear. I usually plant four or five tomato seeds per pot and carefully separate each out into individual small pots once they have grown their second set of leaves. Only handle young plants by their leaves – don’t touch the stem and never touch the roots.
If you don’t want to use up any of your valuable box space with tomatoes, it's a good idea to grow hanging cherry tomatoes. These look rather pretty spilling out of baskets and taste very good when picked sun-warmed and eaten like sweets.
One drawback of the windowsill is that the plants will lean toward the light and become ‘leggy’. If you don’t mind the neighbours thinking you’ve started a cannabis farm, build a cardboard wall on three sides and hang with tinfoil – this bounces the light around and the plants grow far better.
Plants that can be grown outside right now are lettuces, radishes, carrots, beetroots and spinach. Buy a few metres of horticultural fleece (I get mine from the 99p shops) and pin it over bent coat hangers as a simple cloche. This will add a few extra degrees of warmth and get them started faster.
Use the seed compost you bought for sowing indoors to make a line to sprinkle the seeds onto. Try some things you don’t see that often in the shops such as yellow beetroots, white radishes, purple carrots and other variants. But at the same time, do sow classic sturdy seeds you can trust to do well like Boltardy beetroot. Wet the compost before thinly sowing seeds, then sprinkle dry compost on top. Don’t water again at this point, as you will wash everything away.
The secret of a productive and useful salad bed is to sequentially plant. By planting some seeds every fourteen days you’ll keep a good supply rolling through and avoid gluts. Radishes grow surprisingly fast and they need to be eaten when small or they become too peppery and hot (and will eventually become hollow), so you don’t want to plant too many at a time.
As well as sowing single lettuces, buy a packet of ‘cut and come’ again lettuces. Sow a cigar-thick line and don’t thin them out as they grow, just give them a haircut with scissors when a few inches high. This will give you a nice mix of colours and flavours and the plants will happily carry on growing after their trim, letting you harvest at least four or more times over the coming weeks. Just make sure you water them well, as they hate drying out. Don’t forget that when you come to thin out your beetroots and carrots you can use the spare whole seedlings for the plate – providing you with your very own micro-herbs and vegetables.
As for pests and diseases, slugs and snails can be a problem. You’ll have to find your own solution here, but I confess to using a light dusting of slug pellets. Organic defences are available, but I’ve never found they really work. I did once try executing a snail a day with an airgun, to warn the others, but it never seemed to have any effect.
Basil seeds can be germinated on a warm windowsill in April using the pot and freezer bag method, but don’t bury the seeds; just sprinkle on the surface and wet down. Amazingly, when the first true leaves appear, they may only be the size of a pinhead but will smell beautifully of basil when lightly touched. For me, that aroma always says a new season has started.
Parsley is worth sowing now indoors or out; I prefer the frizzy variety for flavour. It is notoriously difficult to germinate; old gardening lore says that it’s ‘the Devil's herb’ and the seed has to go to the Devil and back seven times before it begins to grow. In fact, after sprinkling the seed and lightly covering it with soil, douse gently down with boiling hot water – this softens the seed and increases your chances of germination. It still won’t be quick, but have faith (and damn the Devil)!