Flowers​

• Sow hardy annuals, such as love-in-a-mist and pot marigolds, as well as native wildflowers, into gaps in borders

• Enjoy instant colour by planting primulas and polyanthus in pots and at the front of borders

• Protect the new shoots of hostas, delphiniums, lupins and other vulnerable plants from slugs and snails

• Continue deadheading spring bulbs and bedding, so they don't waste energy setting seed

• Plant pineapple lily (eucomis) bulbs in pots for exotic-looking summer flowers

• Sow sweet peas at the base of supports, and transplant those sown in autumn into their final positions

• Spray the new leaves of disease-prone roses with fungicide to control mildew, rust and blackspot

• Take basal cuttings from clumps of perennials, such as delphiniums, campanulas and lupins

• Prune hydrangeas, cutting back the old stems to a healthy shoot lower down

• Reinvigorate mature clumps of hardy perennials, such as hostas, asters and daylilies, by dividing and replanting

• Sow sunflowers in a sunny, open site, then water regularly and protect seedlings from slugs and snails

• Check for aphids on roses and rub them off before they develop into major infestations

• Add aquatic plants, such as waterlilies and irises, to garden ponds

Fruit and veg

• Plant second-early and maincrop potatoes

• Place cardboard collars around the stems of brassicas to deter cabbage root fly from laying their eggs

• Pinch out the tips of broad beans if they're covered in aphids, or spray shoots with soap-based solution

• Sow outdoor varieties of tomatoes, chillies and courgettes in pots, so they're ready to plant out in late May or June

• Divide clumps of hardy herbs, such as lemon balm and chives, then replant in pots, borders or a dedicated herb bed

• Sow small batches of rocket and other easy salad leaves

• Continue planting bare-root asparagus crowns and Jerusalem artichoke tubers

• Sow flowering companions in the veg plot, such as pot marigolds and borage

• Continue planting batches of garlic, shallots and onions every few weeks to extend the cropping period

• Sow herbs such as parsley, coriander, dill and chamomile in a sunny bed or container

• Protect emerging seedlings from slugs and snails

• Sow fast-growing crops, such as radishes, to make the most of any temporary gaps
   

Greenhouse

• Prick out seedlings growing in pots and trays as soon as they produce their first true leaves

• Sow sweet peas in deep pots and keep them frost-free in a greenhouse or on a sunny windowsill

• Start feeding houseplants once a week with liquid fertiliser, continuing through to autumn

• Sow quick-growing microgreens, such as kale and mustard, for nutrient-rich pickings in just a few weeks

• Transplant greenhouse tomatoes into growing bags or large containers and tie in the stems to supports

• Plant up hanging baskets and pots with summer bedding, but keep indoors until after the last frost

• Sow herbs in pots or trays, including basil, chives, parsley, fennel and coriander

• Thin out heavy fruit sets on peaches and nectarines, leaving fruits about 10cm apart

• Sow runner beans, French beans, cucumbers, courgettes, pumpkins and sweetcorn in pots

• Pinch out the shoot tips of fuchsias to develop bushier plants

• Attach guttering to the greenhouse and install a water butt, so you can make good use of April showers

• Clean greenhouse glazing to let in as much light as possible

• Maintain good plant hygiene, picking off faded blooms and dead leaves before fungal diseases can take hold

• Open greenhouse doors and vents on warm days, or install automatic vent openers, to improve air circulation
   

• With thanks to BBC Gardeners' World