What to do in the vegetable garden in March

With March comes spring, and things start to get underway in the vegetable garden. March can still be pretty cold, even at times even snowy. Hardier crops can be sown outside, and there are various plants that are worth starting off inside. However, it is easy to get carried away and sow too much too early. Because of how varied the weather can be, it is difficult to give hard and fast rules as to when to start sowing. One of the best signs to look for is weed seedlings. If the weeds are germinating, start sowing veg. Here is what I am up to in the garden this month:

Planning

Before heading into the garden and sowing seeds willy-nilly to celebrate the arrival of Spring, it is worth thinking about what you want to grow, and what will be grown where. By planning what you will plant where, you can make the most efficient use of your space, and ensure crop rotation. Your plants will be healthier if you don't grow the same type of plant in the same place year in year out. A bit of forward planning makes this much easier. Many crops can't be planted until May when the risk of frost has passed, so you can plant catch crops now - quick growing crops that will be harvested before the main crops go in (or when planted with plants like courgettes and kale, before they get too large). Radishes, lettuces and other salad leaves, spinach and turnips are all quick growing and make good catch crops.

Sowing outside

Many seeds won't germinate if the soil is too cold. Laying black plastic over a bed a few weeks before you plan on sowing in early spring will warm the soil temperature a little. Similarly, using a cloche to cover seedlings will raise the temperature and encourage growth. Different plants have different minimum temperatures for germination. Radish seeds will germinate at relatively low temperatures. I usually sow a row of radishes in very late February or early March under a cloche. Once these have germinated I start sowing lettuce, mixed salads, beetroot (bolthardy is the best variety for early sowings) and kohl rabi. Broad beans can also do well if sown in March. Most other crops should be left until at least April.

Sowing inside

Seeds can also be sown inside and then planted outside later in the year when temperatures are milder. It is easy to get carried away though, and sow too much too early inside. Plants can grow surprisingly fast on a sunny windowsill, and what starts as a small seed tray in March can seem like a jungle once the seedlings have been potted on in April. If you keep plants inside in small pots for too long their growth can be checked. I always sow tomatoes in about mid-March. These are then about the right size to be taken outside in May. Basil will grow well on a sunny windowsill, and can be sown in March. Chillies should be sown inside by March at the latest.

Onions, shallots and garlic

I like to sow my onions and garlic in autumn, which means by March they are fairly well established. In March it is worth giving them a bit of TLC by weeding and feeding them. Alliums don't like competition, and you will get a much better crop if you keep them well weeded. I give them an early spring feed by sprinkling some concentrated and well-rotted manure around them. Onions, garlic and shallots can also be planted in Spring, and March is the ideal month for this. All three are best grown from sets, essentially small bulbs. Spring planted alliums will usually be harvested later than autumn sown plants.

Asparagus and Jerusalem Artichokes

Asparagus has to be grown in the same bed year in year out. If you want to plant an asparagus bed, March is the time to plant out asparagus crowns. See here for my post on creating an asparagus bed. Jerusalem artichokes can in theory be planted in different positions each year, but establish very easily and in practice it is better to create a bed and leave them in the same place for several years. Jerusalem artichokes will grow almost anywhere, and make a good crop for awkward bits of ground behind a shed or next to the compost bin. March is the best time to plant the tubers.

Broad beans and peas

If you sow broad beans or peas in autumn to over-winter, you will find that they start to put on quite a bit of growth in March as the days get longer. Give them some sticks to climb up, and tie them on loosely, otherwise they will blow flat next time you have a windy day. Broad beans and peas can also be sown in March. 

Preparing the plot

If you have not already done so, get your plot ready for the gardening year to come. Weed and cultivate beds, then mulch them. I have paths running between my beds, and top these up with bark chippings in early spring.


Happy gardening!