Ben Vanheems shares some essential tasks to carry out in your garden and allotment for March

---

Top Jobs for March

Plant onions and shallots –

STEP 1: Both shallots and onions can be planted as small, immature bulbs called sets. Shallots are planted from late February and onions from March. Start by raking in a general-purpose organic fertiliser into soil previously enriched with compost or manure.

STEP 2: Use a string line to achieve neat, straight rows, or use canes to mark out the rows. Position them about 30cm (12in) apart then space sets around 15cm (6in) apart within the row. Push the sets into the soil so that only the very tip of the set is poking through.

STEP 3: Birds can sometimes pull out recently planted sets thinking they’re a tasty titbit. If this happens push them back into the ground or, if the problem persists, cover the area with netting or fleece to keep birds off until the sets have rooted and sent out new shoots.

Pests and problems!

■ APHIDS: Fresh growth brings the very first of the aphids. Check over crops, especially fruit bushes, regularly and squash any aphids you find before they explode in population. Predators such as ladybirds will soon be about to help with the invasion.

■ PEACH LEAF CURL: This fungal disease of peaches and related fruits causes leaves to distort and drop prematurely. Avoid problems on wall-trained fruits by covering the branchwork with a screen of clear plastic sheeting until later in spring. This keeps the buds dry while protecting blossom from frost too.

■ FUNGUS GNATS: Also known as sciarid flies, fungus gnats can be a nuisance in warm, very damp conditions where they can damage the roots of young seedlings. Avoid overwatering so compost isn’t constantly wet and set up yellow sticky traps near seedlings to reduce their numbers.

Under cover –

Time for tomatoes

What’s the most keenly anticipated crop of the year? Tomatoes of course, so get on and sow them and start dreaming of the sweet and juicy pickings to come!

Greenhouse and polytunnel tomatoes are always the first to crop. The extra warmth makes all the difference, while also protecting plants from the dreaded tomato blight. Seed remains viable for up to six years if stored correctly, so it’s worth buying a few packets to enjoy a range of fruits. Include cherry tomatoes for pop-in-the-mouth treats, perhaps a variety for fist-sized beefsteak toms and, of course, a fleshy tomato like ‘San Marzano’ for rich, savoury sauces.

Lack of space or time makes ready-to-plant tomatoes an attractive option, particularly if you only want to grow a few plants. If you are considering grafted tomatoes but hesitating over the expense, rest assured you’re investing in more resilient and prolific plants that will easily pay back the initial cost.

Grow an early salad

Start salads like lettuce, baby leaf spinach, radish and spring onion for the first new-season pickings. Sow seeds of leafy salads into module trays – two per cell – then thin to leave the strongest in each. Radish and spring onion can be sown in scant pinches of four to six seeds per cell and left unthinned. Grow them on then plant into beds, pots or larger trays once they have filled their cells. Alternatively, sow direct into greenhouse borders. Thin out rows in stages to avoid overcrowding and improve airflow and light around the seedlings.

Prick out seedlings

STEP 1: Seedlings started off in pots or seed trays will need moving on as soon as they are big enough to handle if they are to thrive. Very carefully jiggle the seedlings out of their nursery container, or use a dibber, pencil or teaspoon to get in under the roots and lift them free.

STEP 2: Now to carefully separate the seedlings, which requires great care to avoid damaging the delicate stems. Use a stick or pencil to work with the seedlings, gently teasing the roots apart. Only ever handle the seedlings by their leaves and do so delicately.

STEP 3: Transfer the seedlings to pre-filled pots or module trays. Make a hole into the compost using your stick then carefully lower the seedling into the hole before feeding the compost back in around the roots and gently firming. Water them using a watering can fitted with a rose.

Deploy heat

Ensuring a toasty environment is the best way to speed up germination and achieve a better success rate. Heated propagators often include a thermostat to accurately set the temperature, so you can provide exactly the right conditions for what you’ve sown. Don’t forget to open vents to ensure good ventilation.

Heat mats or warming pads are another option and can be rolled out on top of staging to give an instant propagation area. The gentle heat will permeate up into the compost, boosting germination rates, while a layer of capillary matting between the mat and pots can improve humidity and encourage steadier moisture levels.

Key Jobs for March

■ WATCH FOR HARD FROSTS

Remember that bitterly cold March a few years back? If harsh frosts threaten you may need to protect greenhouse propagation areas with a little extra insulation. Throw horticultural fleece over vulnerable seedlings to keep the chill off. Use a heavy-duty fleece of at least 30gsm.

■ SET UP SUPPORTS

Why not get ahead and set up supports for climbing and vining plants now, before things get hectic? Run thick-gauge wire at roof level then tie on lengths of string to dangle down for your vertical supports. Use thick string for this, as plants will get very heavy.

■ HAND POLLINATE

Under cover peaches and nectarines may need hand pollinating to guarantee fruit set. Use a soft artist’s brush and simply tickle it into each bloom to transfer the pollen on to the stigma at the centre of each flower. Repeat a few times over several days for best results.

■ CLEAR WINTER CROPS

Ragged and tired winter crops should be removed from greenhouse beds by the end of the month. Clear away all crop debris and weeds then top up beds with a layer of fresh, well-rotted garden compost to recharge lost nutrients ready for your summer staples.