The Vegetable Garden in April 2021
Hi folks, I hope you all had a good Easter break. I don't know what the weather has been like for you but we have had a very pleasant few days with warm sunshine and a definite whiff of Spring. While I write this, however, hail is rattling against the windows of my office which is a good illustration of just how changeable April can be. I know I always urge caution in early spring but April is one of those months that will easily catch you out.
For most crops, the soil is not warm enough for seeds to germinate and the weather is too harsh for emerging seedlings. Having said that, April is one of the busiest months in the garden as we prepare beds and start seedling plants under cover so we are ready to plant in May, only 3 weeks away.
Getting Organised Anyone who knows me will be sniggering at this piece of advice as I am not well known for my organisational skills. The image below is from my sowing calendar for our new vegetable growers course and I have to say it is the best morning's work I ever did. I am sure you have heard of Google already, they are unlikely to need any further promotion from me but, as it happens, I set this up on Google Calendar. No doubt my garden plan has now been scrutinsed by the CIA or is being used by wily marketers to sell me more sausages but I don't care, this free tool is very handy.
It took a couple of hours to add the sowing dates for the stuff I am growing this year (taken from the plan I shared in a previous mailer). I have also added sowing dates for follow on crops so am happy that I will always have plants ready to go in when space comes available. Anyway, I am just saying it is very helpful to have the season plannned on an easy to edit calendar. Whatever system you use, it takes a lot of the stress and uncertainty out of it.
Horticultural Fleece - Your April Saviour We need to keep a very close eye on the weather forecast in April and be alert to the possibility of frost. As I mentioned a couple of weeks ago, potato shoots (which will be coming up in April) are easily damaged by freezing temperatures so will either need to be earthed up (pulling soil up around emerging stems) or covered by a layer of fleece.
Apart from protecting from frost, fleece also protects from the worst of the weather and is invaluable for starting off crops in early spring. Only this weekend I used it to cover onion and shallot sets (to prevent birds from pulling them up) and covered an early planting of broccoli calabrese to help it get established. I also use it inside the polytunnel on cold nights to cover tomatoes or peppers on the heat bench as a polytunnel provides very little frost protection (typically only one or two degrees).
Hardening off with fleece It is common (and sensible) practice to gradually introduce plants grown under cover to cooler outside temperatures if they are to be planted outside. In reality, while polytunnel or greenhouse started plants will have benefited from warmer daytime temperatures, they will still have experienced significant cold at night (in an unheated tunnel) so have already been hardened off to an extent. In my experience planting out and covering with fleece for the first 2-3 weeks completes the process with the benefit of the roots getting established in the soil.
Preparing vegetable beds The best way to prepare your soil for planting, if not done already, is to apply a 3-5cm layer of well rotted garden compost to the soil surface, there is no need to dig it in. Before applying remove any weeds, especially deep rooted plants like dock or dandelion.
I understand not everyone will have enough compost to hand (by compost I mean nutrient rich rotted kitchen and garden waste rather than potting compost) so we do supply an excellent product, 'Envirogrind' which is the closest you will get (in some ways better) to good garden compost. I have included a link at the bottom of the page.
If you wish to feed soil in containers or raised beds and are not able to bring in bulky compost, I think the best all round natural feed is either blood fish and bone or a seaweed-poultry manure pellet. Both are slow release fertilisers and, while they won't do the soil building that compost does, they do add to the soil. I would rake in either one at 200g per square metre, a week before sowing or planting.
Weeds it is also a good idea to start your weeding regime row, even if there are few weeds about as they will soon catch up. Hoeing of beds now will stimulate the soil surface by breaking any crust and bring some weed seeds to the surface to germinate. Any weeds that sprout from the disturbed seeds are hoed off which results in a top layer of soil relatively free of weed seeds, a technique referred to as a stale seed bed.
What to sow in April As we've said, there is very little you can sow direct into the soil in April but that doesn't mean there is no sowing to do, quite the opposite. You need to become a mini plant factory as you want an army of 3-4 week old seedling plants ready to go outside when it is warm enough in May.
Most seeds will need a little heat (18˚C for outdoor crops, 21 - 25˚C for warm climate crops) to speed up germination so will need to be placed indoors on a sunny windowsill or in a heated propagator if you have one. I prefer to start seeds in modular trays (pictured above) as the little plugs produced are quick and easy to plant out without any root disturbance.
Sowing for planting out in May Seeds for sowing indoors and planting out in May include: Beetroot, peas, early Brussels sprouts, cabbage, calabrese, cauliflower, kale, chard, kohl rabi, leeks. spinach, spring onions, rocket, lettuce, radish, turnip and swede, all can be sown in modular trays.
I germinate all of the above at 18˚C and take off the heat as soon as they come up. I place plants on the floor of the polytunnel on old shipping pallets to keep them off the cold ground and prevent roots growing into the soil. If a hard frost is forecast I will cover with fleece but otherwise leave them to tough it out. Towards the end of the month, if they are growing too fast for their trays, I will put them outside on pallets to slow them down, covering with fleece at night especially if frost is forecast.
Sowing for polytunnel planting in May It is a little late to sow tomatoes or peppers in April, I am not sure I would chance peppers but you can still sow tomatoes if you get on with it. I would recommend cherry tomato varieties for late sowings as they ripen quicker so you will get more from the season, it will definitely be too late for large beefsteak types.
Towards mid April you can sow cucumber, courgette, pumpkin, squash, french bean, runner bean, and sweetcorn. Cucumber, courgette, pumpkin and squash will germinate better at 22-25˚C but all will germinate at 18˚C if you don't have separate propagators. A centrally heated room is usually around 20˚C so all vegetables will germinate on a warm windowsill. Once they have come up I would reduce the temperature to 14-16˚C unless you are using growlights or seedlings will become leggy, I use a heat bench in the polytunnel and usually cover with fleece at night to be on the safe side.
If courgette, pumpkin or squash are to be grown in the tunnel, April sowing is best but if they are to be planted outside I would delay sowing until early May.
Sowing or planting outside I will also be continuing to plant potatoes, my second earlies went in on Sunday and will be followed by maincrop varieties towards the middle of the month. If broad beans have not been sown already they can go in, as can early peas but there is a chance they will be eaten by mice. If mice have been a problem in the past, sow indoors in modules and plant out 3-4 weeks later.
If you are in a warmer part of the country you could also sow early carrots, early beetroot or parsnips outside in mid April but I prefer to wait until conditions are more favourable in early May. If you are trying early outdoor sowings they will definitely benefit from fleece protection.
That's it for now, I will see you next week!