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Gardening in Italy?→ April’s almanac for the Italian climate
ALMANAC · UK CLIMATE

The garden in April

April is the month everything wants to happen at once. Growth accelerates, seed-sowing is in full swing and garden centres fill with bedding plants — many of which will be killed by a frost if they're planted out now.

The key skill in April is timing. Sow and plant hardy things freely, start hardening off the tender ones, and keep fleece within reach: clear nights can still bring frost right to the end of the month.

UK and similar cool temperate climates. Colder gardens should treat the tender-plant advice as applying into mid or late May.

AT A GLANCE

Spotlight: hardening off, step by step

Seedlings raised indoors have soft leaves that have never met wind, cold nights or direct sun. Planted straight out, they often scorch, stall for weeks or collapse. Hardening off is simply a gradual introduction over two to three weeks.

Week one: put the trays outside in a sheltered, lightly shaded spot for a few hours on mild days, and bring them in every night. Week two: leave them out for the whole day and in a cold frame or porch at night, with the lid open on mild nights. Week three: leave them out day and night, covered with fleece if a cold night is forecast. Then plant out.

Watch the forecast rather than the calendar. Hardy plants like sweet peas, lettuce and snapdragons can finish hardening off in April; tender ones — tomatoes, cucumbers, zinnias, busy lizzies — should only be fully outdoors once night temperatures stay above about 10°C. Plants bought from a garden centre that were kept under glass need the same treatment, even if they look sturdy.

TomatoCucumberZinniaBusy lizzieSweet pea Planting out (hardening off) ›

Jobs this month

Sowing season

Warmer soil means most hardy crops and annuals can be sown direct. Tender vegetables and flowers are still sown indoors, ready to plant out after the last frost.

Sow carrots, beetroot, lettuce, chard and peas direct in short rows every few weeks. Propagation: sowing seed › CarrotChardLettucePea
Sow cucumbers, melons, courgettes and squashes indoors in individual pots with warmth. Sowing in trays under cover › CucumberCourgette
Sow zinnias, cosmos and French marigolds in modules under cover. Sowing in trays under cover › ZinniaCosmosMarigold
Plant sweet peas out against their supports and pinch the tips. Staking & supporting plants › Sweet pea

Hardening off

Plants raised indoors need two to three weeks of gradual exposure to outdoor conditions before planting out. Skipping this step is why many seedlings stall or scorch after planting.

Put seedlings outside during mild days and bring them in at night for the first week. Planting out (hardening off) ›
Move overwintered pelargoniums and fuchsias into a cold frame on mild days. Planting out (hardening off) › PelargoniumFuchsia
Cover young growth of pieris, hydrangeas and new potatoes if frost is forecast. Protecting plants from frost › PierisHydrangeaTomato

Borders, shrubs and lawns

This is a good month to plant perennials and evergreens, and to prune spring-flowering shrubs as their flowers fade.

Prune forsythia and flowering currant after flowering. Pruning shrubs (general principles) › ForsythiaFlowering currant
Tidy heuchera and bergenia leaves and replant heuchera crowns that have lifted. HeucheraBergenia
Start mowing lawns regularly, with the blades high at first. Lawn basics ›
Plant summer bulbs such as lilies, gladioli and crocosmia. LilyGladiolusMontbretia

Houseplants

Houseplants are growing again. Water and feed more, and divide or repot those that need it.

Repot orchids that have finished flowering if the bark has broken down. Repotting houseplants › CymbidiumDendrobiumMoth orchid
Cut back leggy syngoniums, yuccas and crotons and root the cuttings. Propagation: taking cuttings › Arrowhead plantYuccaCroton
Divide aspidistras and marantas that have outgrown their pots. Propagation: division › Cast iron plantPrayer plant

Sow and plant

Sow
  • Carrots, beetroot, chard, lettuce, peas, spring onions (outdoors)
  • Cucumbers, melons, courgettes, squash (indoors)
  • Zinnias, cosmos, rudbeckia, tagetes (indoors)
  • Hardy annuals direct where they'll flower
Plant out
  • Summer bulbs
  • Perennials, shrubs and climbers
  • Main-crop potatoes
  • Sweet peas raised under cover

Watch out for

Late frostA clear, still night is the warning sign. Tender seedlings put out too early are the usual casualty.Lily beetleBright red beetles on lilies and fritillaries; pick them off as soon as they appear.AphidsColonies build up quickly on roses and soft shoots in warm spells.

Questions

When is it safe to plant out bedding plants?

After your area's last frost, which in most of the UK means mid to late May. Hardening them off through late April and early May gets them ready.

Can I sow carrots in April?

Yes — April is one of the best months. Sow thinly direct in the ground, since carrots don't transplant, and cover with fine mesh against carrot fly.

Should I feed my houseplants now?

Yes, from April most houseplants are growing and benefit from a balanced feed every few weeks at the strength on the label.