A touch of frost

But be warned, if you risk planting tender plants out before the last frosts have passed, it could ruin all your hard work of the previous months.

Depending on where you live, a late frost can hit in late May or even in June, reducing your tender plants to shrivelling corpses, so it's prudent to be cautious about planting out or removing protection too early and to p lant tender bedding plants out after the danger of frost has passed.

It's best really to sow seed of frost-tender vegetables including French and runner beans, courgettes, marrows, cucumbers, tomatoes, squashes and melons, in April under cover because they are going to take four or five weeks to establish before they can be put outside, so that way they are timed to be planted out after the last frosts are over.

Anything grown in a frost-free greenhouse such as patio plants and frost-tender vegetables will need hardening off before being planted outside, to acclimatise them slowly to outdoor conditions. Harden them off two to three weeks before planting.

They can be hardened off in a cold frame or simply moved outside into a sunny, sheltered position during the day and then brought back inside at night.

For new tender plants which are already in the ground but need some protection, cloches are always a good idea and can be removed during the day when the temperatures rise.

Protect new shoots and fruit tree blossom with horticultural fleece and cover plants in an unheated greenhouse with newspaper.

If spring frosts have affected tender young growth, causing scorching and pale brown patches to appear between the leaf veins, often on the exposed and top edges of the plant, don't give up just yet as the plant may still be alive.

Many plants can be surprisingly resilient and may well rejuvenate from dormant buds at or below soil level. This takes time so recovery may not be seen until early summer. If the plant is of high value or it is not essential to fill the gap, consider leaving the damaged plant in the ground until mid-summer. If no re-growth has appeared by then, replace the plant.

If you want to plant up hanging baskets early with young plants, make sure you take the baskets under cover at night, keeping them in a sheltered porch or similar area. Troughs and patio tubs which you want to plant up with vulnerable plants should also be treated similarly, or covered at night with horticultural fleece.

Frost problems are often made worse where plants face the morning sun, as this causes them to defrost quickly, rupturing their cell walls. Periods of cold, frosty weather during April and May can also kill blossom and damage fruit. Camellia and magnolia are particularly vulnerable and can be ruined in a single frost.

Avoid planting tender plants in frost pockets, which tend to be at the lowest point in a garden, as cold air and frost always descend and settle at the lowest point. Instead, plant them in a sheltered spot, under large trees and shrubs or against walls, to give them some heat and protection during the winter.

And don't give up just yet if your plants succumb to frost - if you wait till early summer you may see some signs of growth underneath the damaged parts and can cut back the dead growth to give the new growth a chance to catch up.

BEST OF THE BUNCH - Bluebells

There are some amazing bluebell woods throughout the country - and some of the National Trust gardens house the best - where carpets of these pretty flowers dominate the vista. The wild bluebell, Hyacinthoides non-scripta, provides the English countryside with a splash of spring colour, looking stunning in the grass under trees with white or grey bark such as the British native birch. In domestic gardens, they will look natural in any areas with dappled shade provided by trees or large shrubs. Bulbs should be planted in autumn, 4-6cm deep in clumps of 20 or more. You'll need to plant a lot of clumps to make an impact and if you want to plant them in grass, lift patches of turf and then plant the bulbs accordingly. The Spanish bluebell, Hyacinthoides hispanica, has been much maligned for its tendency to breed with the English bluebell, invading native populations, so if you are planning to grow the Spanish type, keep them well away from native bluebell populations.

GOOD ENOUGH TO EAT - Stop cabbage root fly

The white maggots of this destructive pest which looks like a house fly eat the roots of leafy brassicas and tunnel into the roots of turnip, swedes and radish and unfortunately there are no insecticides which will stop them. Try growing them under horticultural fleece or insect-proof mesh, or place brassica collars around the stems of young cabbages, cauliflowers and Brussels sprouts. The collar prevents the female fly placing eggs on the soil surface close to a host plant. Eggs deposited on the collar often dry up and fail to hatch. Affected plants show poor growth and may wilt and die, especially new transplants in early summer. And make sure you practice crop rotation because cabbage root flies can emerge from overwintered pupae in the soil under the fleece cover if the host plant is grown in the same place in successive years.

WHAT TO DO THIS WEEK

:: Put new aquatic plants in the pond either in the soil at the bottom or using special aquatic baskets

:: Take cuttings of new shoots of tender plants including diascia, fuchsia, pelargonium and verbena

:: Mulch around shrubs to retain moisture

:: Sow basil, parsley and chives in the greenhouse or on the windowsill

:: Water seedlings which can easily dry out when the weather warms up

:: Support peas and beans sown earlier

:: Harvest the first overwintered spring onions

:: Plant summer bulbs for patio containers, including patio dahlias, compact lilies and dwarf gladioli

:: Plant asparagus in a prepared bed, planting all-male, named varieties which have fatter and more succulent spears than females and don't produce seeds

:: Divide overgrown marginal plants