The Vegetable Garden in April

The Vegetable Garden in April

I don't know what it has been like for you but March has been a relatively dry month in my garden which meant I was able to do a bit more outside than I normally would. While it is still too early to sow or plant most crops outside, April is all about preparing your garden for what will be a very busy May. The point is that things happen so fast next month that you can easily get overwhelmed if the basics like tidying, soil preparation or weeding has not been attended to.

April is also the month that the majority of vegetable seedlings are sown if you are growing in modular trays for planting outside in May. You will remember that most outdoor vegetables take approx 4 weeks from sowing the seed until they are large enough to plant out so if you want seedlings ready in early May, you need to sow them in early April. I will cover what and when you can sow at the end of this article.

Garden Succession Planting Plan

Planning - new succession plan
April is also about planning the garden and deciding what goes where for your spring sowing and planting but also what can replace crops that are harvested in summer (succession growing). Early or 'new' potatoes, for example will be out of the ground in late June when there is still plenty of life left in the season so the bed can be used for a follow on crop. You can see in my 2022 plan above that new potatoes (bottom left) will be followed by late leeks (which I will be growing in old fish boxes for transplanting when the beds free) or by winter savoy cabbage (again, I will have seedlings ready to plant in summer).

Taking an hour or so to work out a plan makes a huge difference and will save you a lot of head scratching and stress in May. Planning where crops are going means you can organise succession growing and crop rotation but it also means you can get your soil prep right for the plants you want to grow. For example, hungry crops like cabbage, Brussels sprouts or caulflower like a firm footing and will need plenty of nitrogen (so they like manure) whereas carrots need a light soil with plenty of phosphorous for root growth. Also, while cabbages love manure, it is not advisable to add it to a carrot bed or the roots will fork looking for the nutrient pockets

Preparing Raised Beds

Preparing beds
Once you know what goes where, you can start preparing your beds if you haven't done so already. The reason the dry weather in March was so welcome is the soil also dried a little after winter making it safe to work. You should avoid working wet soil if possible because it drives out the air spaces and compacts it so, if it's wet, you can stay on the sofa.

We have already covered soil preparation so I don't want to sound like a stuck record but try to add as much organic matter e.g. garden compost, municipal compost, well rotted manure, old mushroom compost, seaweed or whatever you can get your hands on. It is much better to add any soil feed to the surface of the soil rather than digging it in to avoid compaction (as above) but also because digging breaks up both beneficial fungal networks and burrows (which aid drainage) made by the creepy crawlies in your soil.

Mulching Raised Beds

There are loads of options for soil and plant feeds but, if you want to keep it simple, you could add municipal compost to all your beds with an even covering of 4-5cm and rake it into the first 10cm or so of the soil surface. If you intend to grow heavy feeding crops like brassicas (cabbage family), courgettes or to pumpkins, also rake in 'Seafeed' seaweed and poultry manure pellets at approx 200g per square metre. That should be nearly all you need for the season.

As soil temperatures begin to rise in April, deep root perennial weeds re-awaken and annual weed seeds begin to germinate. If weeds get a foothold, they become a chore but if dealt with early they are easy (and quite satisfying) to control.

There is no point in removing the tops of deep root weeds like dandelion or dock as they will quickly re-appear; spend some time with a trowel or narrow spade loosening the root and removing as much as possible. If the tip of a deep root breaks off underground it doesn't really matter as the remnant probably won't have enough stored energy to make it to the surface but get as much as you can.

Hairy Bittercress Weed

Annual weeds like the very common hairy bittercress (above) will flower and produce seed surprisingly quickly, it can complete a full lifecycle from a single seed to a plant producing hundreds of seeds in only 5-6 weeks. If bittercress or any of its friends (e.g. chickweed, fat hen or groundsel) is allowed to product seed in April, you will have a lot more work to do for the rest of the year so best to keep on top of them now.

Thankfully, annual weeds have shallow root systems and are very easy to remove when small by hoeing the surface of the soil. If the day is dry and sunny, they can be left on the soil surface where they will die but if it's damp, collect them up. If you have left it late to tackle them and they are beginning to flower, they may have viable seeds so it is best to remove them.

Oscillating Hoe

Feel good factor
If you want to get more satisfaction from hoeing your beds, imagine you are having your back scratched, I think the garden feels the same way. The other advantage of shallow hoeing, apart from controlling weeds, is that it breaks the top crust of the soil which improves drainage and allows beneficial organisms in the top layers of the soil to breathe. Scratching your garden's back regularly throughout the season keeps your soil life happy which in turn keeps your plants happy; it is a task with multiple benefits so should also make you happy!

As with soil feeds, there are many hoe options but, again, to keep it simple, the oscillating hoe is the best in my opinion. It has a thin, sharp blade (that actually sharpens as it wears) and cuts on both the push and pull stroke so is a very efficient tool. Alys Fowler of BBC Gardeners World fame pronounced it 'the best hoe in the World' which I think pretty much covers it.

Onion sets

Onions and Shallots
If you haven't got your onion or shallot sets planted yet, you still have time in early April. In fact. late planting can be beneficial as cold weather in March can cause sets to bolt later in the season.

Growing onions from sets is probably one of the easiest crops to grow but the quality of the sets you plant is important. For those new to growing onions, they can be grown either from seed or 'sets' (pictured above) which are baby onions that were lifted the previous season before they had a chance to bulk up. The sets are stored over winter and re-planted in spring to grow and produce finished onions.

Choosing the best onion sets

I have probably said this before but the best onion sets will produce the best onions so, as a rule of thumb I usually end up discarding about a third of the onions in a bag. What you are looking for are medium sized (in relation to the rest of the onions in the bag) sets which are nicely rounded and feel good and firm when squeezed.

You might think that sets which have already sprouted will give a head start but this is not the case, they will not produce a good mature onion. I would therefore discard any sprouted sets or any narrow, skinny or very large ones and any with signs of mould or rot. Once planted, I would cover them with fleece for an few weeks until the roots have anchored them into the ground and they have begun to sprout, otherwise birds are like to pull them up (I presume they think they are snails).

Deep watering a greenhouse after winter

Deep watering a greenhouse or polytunnel
If you have a greenhouse or polytunnel that has been unused for the winter the beds will be very dry by now. Bear in mind that watering when you are sowing seeds or planting seedlings in the soil will only wet the surface, it will take a lot more irrigation to address the moisture deficit deeper down. Large indoor plants like tomatoes or cucumbers have deep taproots that will be looking for moisture below so you will need to build moisture levels back up.

The most effective method is to dig holes of about a spades depth in the soil and fill with water. The pools will slowly drain into the surrounding soil at which point you fill them up again. When the water takes a long time to drain away, the soil is properly saturated and the holes can be refilled.

What to sow in April - close up of vegetable seedlings

What to sow in April
As regards what to sow in April, this will depend on whether you intend starting seeds off indoors for planting out in May or sowing direct in your garden soil. If you are sowing indoors in pots or trays, you can sow nearly all vegetable crops but for direct sowing outside you will need to wait until May for everything bar peas and broad beans. If you have a warm, southerly garden you could also sow early beetroot, parsnips or carrots from mid month but I always think it is better to wait as warmer conditions will see much faster growth. Maincrop potatoes are planted in mid April which, as we've said is also the cut off for onion and shallot sets.

For indoor sowing of crops which will be planted outside later, you can sow winter leeks, French bean, runner bean, cabbage, cauliflower, Brussels sprouts, calabrese, kohl rabi, rocket, swede, turnip, lettuce, perpetual spinach, sweetcorn, chard, annual spinach, scallions. All of the above will need approx 18˚C to germinate reliably so if sowing in a greenhouse or polytunnel you will likely need a propagator or heat mat. If growing in the house, make sure the seedlings get as much light as possible by using a bright, south facing windowsill.

What to sow in April - close up of vegetable seedlings

Warm climate crops to be grown in a greenhouse or polytunnel are generally sown from mid April and include courgette, cucumber, pumpkin and squash. It is assumed that tomatoes and peppers have been started already but, if not, they can still be sown in early April. I would suggest sowing cherry tomatoes and smaller varieties of chillis rather than beefsteak tomatoes or large sweet peppers as they will be quicker to ripen from a late sowing.

Horticultural fleece
Just a reminder that outdoor planted seedlings which may include peas or broad beans will benefit greatly from a layer of fleece in April, remember that wet and windy weather is almost as damaging as frost. It is all about shelter in April when conditions can swing from pleasant and sunny to wet, cold and windy in a heartbeat.

Using fleece to harden off seedlings

Hardening off
You will also be aware of the term 'hardening off' which is the practice of getting indoor sown seedlings gradually used to outdoor temperatures before planting them outside permanently. This is done by placing trays outside in reasonable weather but back in at night for a few days which can be a chore if you're busy and have a lot of trays.

My tip is that conditions under fleece will be similar in terms of temperature and protection than those in an unheated greenhouse so a layer of fleece can do the hardening off task for you. I would not recommend this until mid April but if we have a cool May like we did last year, fleece will get you going quicker with less risk of casualties.

Aalsmeer cauliflower head in April

As regards harvesting now, kale plants will be starting to go to seed which, if you get the heads before they flower, are deliciously tender, a but like a lighter version of purple sprouting broccoli. Another real April treat is spring cabbage which will be ready to pick from mid month (sown last Autumn) and overwintering cauliflower. The variety pictured above (which I took at the weekend) shows 'Aalsmeer' which I sowed last summer and is now producing perfect dense heads of creamy cauliflower. If it survives the winter well, overwintering cauliflower has an advantage over summer heads in that there are fewer pests around and, due to lower April temperatures, will stand for longer without going into flower.

I am also harvesting the last of the Brussels sprouts and flower sprouts, clearing and composting the beds as I go. I still have a nice bed of late winter leeks in the garden but these really need to be used soon or they will start to go to seed.

Next week I will be introducing the 'Subpod', an interesting new wormery composting solution that works by burying the unit in the ground. If there is anything else you would like me to cover, let me know!

See you all next week!