Roehampton Garden Society

Maintaining soil and structures and planning ahead

• Although weather is warmer, continue to listen for forecasts of frost warnings and cover vulnerable plants at night. Delay planting out cold sensitive plants if frosts are forecast.
• Weed ‘defensively’; remove weeds before they flower to avoid seeding.
• Continue to keep grass paths manageable by regular cutting.
  Draw up soil around the base of peas and broad beans to support them and increase the rooting area.
• Clean greenhouse glass to improve light levels
  On sunny days ventilate the green house by morning opening and close late afternoon to conserve the heat.
• Earth up early potatoes when they have made 8” growth.
  Plan and prepare planting holes for squashes, adding well-rotted manure.
• Build frames for climbing beans.

Sowing and Growing

• Sow indoors or in the greenhouse Brussels sprouts, cabbage, early leeks, cucumbers, courgettes, peppers and sweet corn.  Sow tomatoes for outdoors.
• Sow herbs; dill, fennel, oregano and thyme, parsley from seed.
• At the end of the month sow tender vegetables indoors, such as runner beans, squash and pumpkins.
• Watch out for signs of damping off in seedlings which can be caused by sowing in cold, wet soil with poor drainage and air circulation and worsened by overwatering. A light covering of vermiculate reduces the problem.
• Direct sow broad beans and early peas.
• Make successional sowings of beetroot, Swiss chard, lettuce, radish, summer spinach, spring onions, lettuce, parsnips and turnips.
• Thin out germinated seedlings and hoe between rows.
• Direct sow early varieties of carrot when the ground has warmed up.  To avoid attack from carrot fly, either sow 18” above ground level or cover with insect mesh.
• Sow annuals to attract pollinating insects such as nigella, single flowered marigolds, comos, Californian poppies.
• Direct sow sweet peas.
• Second early and maincrop potatoes should be planted by the end of the month.
• Once tomatoes have their first true leaves, plant them deeply into individual pots
• Water crops regularly in dry weather.
• Plant out autumn-sown sweet peas.
• Finish planting shallots.
• Plant soft-neck garlic.
• Plant up new asparagus and globe artichoke beds.
• Cover radishes and turnips with horticultural fleece to protect against flea beetle.
• Use fleece to protect blossom of trees such as pears if frost is forecast.
• Net strawberries against bird attack.
• Watch out for early aphid attacks. Early action by manually removing these or hard- spraying with water can reduce likelihood of damaging infestations.
• Feed roses with rose feed.
• Feed soft fruit with a general purpose fertilizer.
• Pick and destroy yellowing leaves of brassicas infected with downy mildew.

Harvesting

• Harvest rhubarb by pulling a few stalks at a time. Put the leaves on the compost heap.
• The first cutting of asparagus is traditionally made after St George’s Day, 23^rd April and the last cutting on the longest day, 22^nd June.

Pruning

• Once leaf buds open, start formative pruning of stone fruit trees such as plum and cherry.
• Pinch out laterals on grape vines to leave one every 30cms and tie in selected shoots.
  

Gardening for wildlife

• Divide or cut back pond marginal plants.
• Prepare a fine tilth before sowing a wildflower meadow patch of cornfield annuals to attract pollinating insects.

Maintaining soil and structures and planning ahead

• Continue soil preparation by hoeing to suppress early weeds and cover with black landscape fabric/ weed suppressant or a thick layer of composted stable manure to warm the soil. Top- dress overwintering vegetables with a general fertilizer.
• Control early weed growth by regular hoeing.
• Nutrient-rich mulches such as composted manure should be spread when the soil is moist and warm, from mid to late spring, just before the main growing season.
• Apply a balanced fertilizer such as growmore or fish, blood and bone around fruit trees and bushes.
• Apply a general fertilizer to all areas required for early crops. Fish, blood and bone or pelleted poultry manure are slow-release so apply now for summer growing.
• To lessen the impact of brassica club root, raise the soil pH by adding lime or calcified seaweed to brassica beds. Some club root resistant varieties are available e.g. Brussels sprouts Crispus, Cabbage Kilaton.
• Cut down autumn-sown green manures and now sow green manures such Buckwheat, Crimson Clover, Fenugreek, Mustard, Phacelia, Trefoil or Winter Tares. These will improve the soil until it is needed for planting.
• Ventilate the green house on sunny days and close up by mid afternoon.
• Clean greenhouse panes to maximise light levels.
• If the soil is not too wet start strimming, clipping or mowing grass paths to maintain good paths between plots.

Sowing and growing

• Sow outdoors early cultivars of beetroot, broad beans, peas, early cultivars of lettuce, radish, early spinach, parsnips and turnips. Towards the end of the month early varieties of carrot can be sown.
• Protect young seedlings with fleece or cloches on cold nights, removing the covers in the day.
• Sow indoors or in the greenhouse Brussels sprouts, cabbage, summer cauliflower, celery, celeriac, early leeks and tomatoes, cucumbers, courgettes, peppers and chillies.
• Germinate aubergines, cucumbers, peppers and chillies in a heated propagator if available.
• Start herbs from seed. Sow dill, fennel, parsley and sorrel in plots to transplant later.
• Annual flower seeds such as cosmos, sweet peas, marigolds, nasturtiums and candytuft can be sown directly as the soil warms.
• Watch out for signs of damping off in seedlings which can be caused by sowing in cold, wet soil with poor drainage and air circulation and worsened by overwatering. A light covering of vermiculate reduces the problem.
• Direct plant shallots and onion sets, just deep enough that the bulb tips are visible above the soil.
• By the end of March, if the weather is warming, plant first early potatoes when the shoots are 2cms long.
• Plant asparagus crowns.
• Prepare trenches for runner beans with well-rotted manure and shredded paper at the base.

Harvesting

• Broccoli, kale and leeks can be harvested now.

Pruning

• Prune blueberries. Promote new fruiting wood by removing up to a third of the old stems at ground level.
• Complete pruning Hybrid Tea and Floribunda roses.

Gardening for wildlife

• Convert an empty flower bed into an annual meadow to attract pollinators to your plot.
• Place bundles of hollow-stems horizontally in sheltered areas for to provide places for beneficial insects to lay their eggs.