April is perhaps the busiest month in the garden. With temperatures fast warming, it’s time to get all your plans in place for the season ahead (but don’t forget about Mr Frost, who can still catch you out!).
By this stage in the season you more than likely already have vegetable and flower seedlings to tend to, along with ambitions to get plenty more sown for a productive and colourful summer season. Hardy annual flowers and vegetables can now be sown outside, directly where you want them to grow, reducing your work load.
April offers the ideal conditions for planting out a wide range of larger container plants, too. Perhaps you over-wintered last year’s sowings of herbaceous perennial plants. They can now be moved from cold frames and nursery beds and planted in their final positions.
Trees and shrubs can also be set out this month to provide shape, structure and ‘backbone’ to your border and container displays. Hardy fruit trees, bushes, canes and runners can all be planted too. Strawberry runners for example are despatching from the nursery now.
With so much to be done this month, the question is how will you fit it all in to your schedule. Our breakdown of essential jobs for April, should help you get your plans and plants in order.
The Flower Garden
Sweet peas sown last autumn or during the winter months should be ready for planting out this month. These tough scented climbers will cope with cooler soils and late spring temperatures, quickly establishing for a show stopping display of early summer colour. Just make sure to harden them off before planting, by placing them outside by day and back under cover each evening for a week or so. Then set them out in well prepared soil, with lots of added manure.
If you haven’t already sown sweet peas you really are missing out. These easy to grow climbers offer some of the best scent and colour for the garden (and for indoor vase displays). Fortunately they can be sown outside this month too. If you don’t have space for the climbing varieties, try dwarf types such as ‘Patio Mixed’ or ‘Dwarf Explorer’.
Plenty of life left in spring containers and bedding displays
Spring bedding plants such as pansies, primrose and bellis, whether set out in the soil or in patio pots and baskets, should have enough reserves to carry on until late May when you can replace them with summer options. To ensure they go the distance, use these three top tips:
- Deadhead: remove all spent flowers to prevent plants diverting their energy on setting seed. Removing flowers encourages more to develop, carrying colour through to summer.
- Chop back: If plants have become straggly you can cut them back by half. They’ll lose their looks for a week or two but will soon be flowering again over neat and tidy foliage.
- Offer a regular feed: With plants in full swing, offer a liquid feed every two weeks to support their growth and encourage the best looking displays.
Ornamental Grasses from Seed
Ornamental grasses add a touch of elegance to mixed summer borders, creating movement with their nodding seedheads, and going on to add autumn interest – the dried golden seedheads and foliage look stunning when caught by an autumn frost. As you make your flower sowings this month, save some space for these classy border additions. Sow indoors or directly outside where they are to grow. Top choices to try include Bunny tails (Lagurus ovatus), cloud grass (Agrostis nebulosa), goldentop grass (Lamarkia aurea) and silky spike melic (Melica ciliate). For a winning mix of annual and perennial ornamental grasses try the Mr Fothergill’s Ornamental Grasses Collection.
Hardy Herb Containers
While tender herbs need to stay on the windowsill, you can get creative with hardy herbs in the garden this month. Not many gardeners have the luxury of a dedicated herb garden, but fortunately most hardy herbs grow under the same conditions and will thrive together in a mixed herb container.
Avoid traditional herb planters with side planting holes, unless you can be sure you’ll keep up with watering. These dry out very quickly and are hard to rewet fully. Instead, select a wide container and add a mix of herbs as you would a mixed summer patio container. A 50:50 mix of multipurpose compost and loam-based John Innes no.3 is ideal for herb containers. Top tip: Use a high nitrogen feed with low potassium levels when feeding herbs. This will encourage lots of leafy growth rather than flowers.
- Deadhead spend spring flowering bulbs such as daffodils and tulips. But leave their stems and foliage to die back naturally, placing energy back into the bulbs for the best display next year.
- Treat fences, sheds and other wooden structures with a paint or preservative before spring growth makes access difficult.
On The Veg Patch
When it comes to vegetable sowing don’t, do it all in one hit, this will simply lead to a glut of produce later in the year. Instead, adopt the successional sowing method - smaller batches of seed sowing done every two weeks or so, which leads to a constant supply of ready to pick produce through the season, with few gaps and no gluts.
Hardy vegetables to sow outside this month:
Also plant out onions sets and seed potatoes.
Hand pollinate early fruit trees
Early flowering fruits such as cherries, greengages, nectarines and peaches will benefit from hand pollination, as it may be still too early for most pollinating insects to do the work for you. Use a small artist’s paint brush to gently transfer pollen from one flower to another.
In The Greenhouse/ On The Windowsill
Focus on Half Hardy Annuals
With hardy annual sowings now being made outside, you can give windowsill and greenhouse space over to half hardy annuals that need a bit of extra warmth to get started. If this is not possible, wait until the second half of May and sow half hardy annuals outside where you want them to grow.
If sowing isn’t your thing, or you’ve simply run out of space already, our bedding and vegetable plant varieties become ready for despatch this month. Here we’ve done the finicky first-stage work for you, simply pot up our plug plants on delivery and grow on in frost-free conditions until ready to plant out in late May/early June. If you’ve got the space to grow them on, you can even set them directly into hanging baskets and patio containers, for effortless displays come summer.
Early start on summer herbs
It’s too early and too cold to think about sowing or planting tender herbs outside, but you can make an early start with your favourite flavour boosters this month by sowing small pots on a sunny windowsill. Basil, coriander, oregano, chervil and other frost tender herbs can be sown every four weeks or so between April and July for consistent supply of succulent fresh leaves.
Sow outdoor tomatoes, chillies and peppers
Greenhouse growers will already have their tender crops well underway, but if you grow tomatoes, peppers and chillies out in the garden, April is the ideal month to sow their seeds. This ensures that the plants will not get too big before planting out in early June, once all threat of frost is gone.
Sow seeds in trays, modules or small pots of multipurpose compost and set on a warm windowsill or in a heated propagator, aiming for around 21C. Turn off the heat and remove covers once the majority of seedlings are on show. Transfer individual seedlings.
Transplant early tomatoes, chillies and peppers
Greenhouse growers can now prepare greenhouse borders, or stock up on grow bags and containers ready to plant out or pot up tomatoes, peppers and chillies. Other things to plant in the greenhouse include watermelons, cucumbers, sweet potatoes.
There’s a simple pleasure in watching a towering sunflower develop through the season, especially when you’ve raised it from seed yourself. If you are looking to grow a giant this summer, it pays to start as early as possible, giving your plants the longest growing season. Sow sunflower seeds indoors through April, ready for hardening off in late May for planting out.
For the tallest plants try Sunflower ‘Giant Single’. For the largest flower heads and lots of edible seeds, try Sunflower ‘Titan’. For a shorter, decorative addition to your summer displays try Sunflower ‘Sunburst’, ‘Magic Roundabout’ F1 or ‘Little Leo’.
On sunny days, greenhouses can quickly overheat- even this early in the season. Prevent this with a three pronged approach:
- Open vents and doors on hot days (think about fittings auto openers).
- Put up shade netting or shade paint so vulnerable plants and young seedlings don’t frazzle on sunny days.
- Damp down the floors and staging once or twice a day to raise humidity levels and bring the ambient temperature down.
What to prune in April
- Stone fruit trees such as cherries and plums can be pruned now that the risk of contracting silver leaf disease has passed (it enters plants on winter rain).
- Fig trees to can be pruned to keep their shape and size.
- Check all shrubs and hedges for bird nesting activity before carrying out any pruning. If nests are spotted, wait until summer before trimming your plants – it is illegal to intentionally damage or destroy the nest of any wild bird whilst it is in use.
- Winter-stemmed shrubs like Cornus and Salix should be cut back hard to encourage new shoots for next winter’s display.
- If not already done, remove any dead foliage growth left on herbaceous perennials before new growth takes over
By mid spring weeds start to grow rampantly, annual weeds will be germinating freely in unworked soils, and perennial types will be setting down roots to really take hold.
Ideally dig out perennial weeds by hand, but be thorough. Many perennial weeds, including dandelion and couch grass, will regrow from the smallest piece of root left in the soil. If hand weeding is not possible use weedkillers responsibly, seeking organic options where possible. The best way to keep on top of annual weeds such as chickweed and shepherd's purse is to hoe your border and veg patch soil at least once a week. Aim to do this on a sunny or windy day, so dislodged weeds wither on the surface – rainy weather can actually set them back into the soil!