- Watch out for late frosts: protect tender plants with fleece.
- Tidy borders. Weed ‘defensively’ by pulling up weeds before they flower.
- Keep pests off brassica and carrots by covering crops with horticultural fleece.
- Look out for early aphid attack. Prompt treatment helps prevent colonies establishing.
- Feed with a general–purpose fertiliser like bone or fish meal.
- Apply mulch and put up supports for perennials.
- Remove flowers from strawberry plants planted after September last year.
- Formative pruning of plum & cherry trees can start once leaf buds open.
- Plant out pot-grown broad beans 6-9 inches (15-23 cm) apart, after hardening them off. Space rows 18 inches (45cm) apart.
April is ideal to sow a wide range seeded crops directly into prepared drills, including:
- broad beans
- khol rabi
- spring onions
- swiss chard
- summer cauliflower
- Plant ‘softneck’ garlic such as ‘Picardy Wight’ up to the end of April. Soft-neck garlic have no flower spikes and often have more cloves to a bulb than ‘hard-neck’ types.
- Finish planting onion and shallot sets by mid-April.
- Plant chitted potato tubers in April, starting with first earlies through to main crops at the end of the month. Continue planting potatoes; plant second early potatoes early in the month, and main cropping potatoes towards the end of the month.
- Throughout April continue direct-sowing seeded vegetables as listed above.
- Towards the end of April watch out for the caterpillar-like larvae of gooseberry sawfly, which can defoliate gooseberry and red and white currant bushes.
Sow Indoors / Under Glass
- Sow indoors early April: tomatoes, cucumber, celery and celeriac
- Sow indoors late April: zucchini, marrow, squashes and pumpkins & runner and French beans.
- Pot tomato seedlings into individual pots when the first true leaves appear.
- Sow leeks and brassica.
- Sow chard, coriander, parley in a cold greenhouse to plant out later.
- Sow tender vegetables indoors, such as
Flower / Ornamental Garden
- Remove faded daffodil and tulip flowers, leaving leaves to die back naturally.
- Trim lavender: take out old flower stems and shorten stems by 1 inch (2.5 cm) if not done in the autumn.
- To ensure good flowering, feed and fertilise roses.
- Inspect roses for black spot; remove affected leaves; use fungicide (RHS, The Garden, April 2013, p.29)
- Spray new foliage of roses against rose mildew using products with a physical action, such as ‘SB Plant Invigorator’ (RHS, The Garden, April 2015, p.29)
- Prune forsythia after flowering has finished.
- Remove frost-damaged growth from shrubs.
- Plant wildflower plugs like cowslip and primrose into unfertilised ground for naturalising.
- Direct-sow annuals such as sunflowers, California poppies, poached egg plants and pot marigolds.
- Plant summer-flowering bulbs such as lilies, cannas, dahlias, gladiola, nerines etc
- Sweet peas can be direct-sown in April.
Division & Cuttings
- Divide and replant herbaceous perennials.
- Look out for new life. Mammals (squirrels, rabbits, foxes, mice etc) as well as frogs, birds and insects are busy breeding and nesting at this time of year.
- Warm sunshine brings out butterflies such as brimstone and comma butterflies.
- In evenings young fox cubs may be spotted.
- Bats emerge from hibernation when night temperatures rise about 5 degrees C.
- Migrant birds from Africa to the UK can now be heard in the dawn chorus, including house martin and swift.
- Cuckoos and swallows are due back in Britain in late April or early May.