Monty Don’s Ultimate April Gardening Guide: Do not do these Mistakes!

As we edge into April, the rain shows no sign of letting up. It touches every garden and every gardener — saturating soil, delaying plans, reshaping the season. Yet, in its own odd way, the mildness has been a quiet gift, allowing most things to thrive in the damp.

Well, most things. The daffodils, usually so cheerful and reliable, have struggled. I suspect the deluge through Autumn and Winter encouraged lush leaf growth at the cost of blooms — a trade that has left many borders looking emptier than usual. They’ll return, of that I’ve no doubt, but their absence this year has been a loss.

The tulips, though, are making their entrance. The bulbs in pots, tucked away under shelter, are lifting their heads in promise — strong, clean, and full of colour to come.

Because of the lingering chill, the season is running early. By the close of March, the cherries, damsons, and crab apples were already wearing their blossom — a flurry of soft colour against leaden skies.

April, though, is the month of light. It’s the turning point — where the days grow longer than the nights, stretching bit by bit, each with more possibility than the last. And when the sun does break through the clouds, it brings warmth, not just brightness.

Even the rain feels different now. Still present, still frequent — but arriving more often in showers than in torrents. Less oppressive. More bearable.

And above all, April carries that unmistakable green — a fresh, vivid emerald in every hedge, every branch, every blade — like walking through a cathedral made of light and leaves.

April Jobs

The key now is to stay ahead — not frantically, but steadily. Mow the lawn, keep on top of the weeds, get perennials planted, finish spreading mulch, and start sowing seeds — but do it all in a way that feels rewarding, not overwhelming. Keep things straightforward. There’s still time.

And if there are jobs you feel you should have tackled weeks ago, there are really only two sensible options: either get on and do them now — a little later than ideal — or consciously leave them for next Winter. Whichever you choose, decide and move forward. The worst thing is to linger in indecision.

HOUSEPLANTS

There’s an incredible variety of plants that thrive indoors, each with its own preferences when it comes to light, temperature, and care. But more often than not, the biggest mistake people make with houseplants is overwatering. To be more specific — the roots are usually too wet, while the air around the plant is too dry.

Most tropical evergreens, for instance, are far happier in a cool spot away from direct sunlight than perched on a sunny south-facing windowsill above a radiator. Desert cacti and succulents are the exception, of course. As a general rule, only water when the compost is completely dry — and when you do, it’s best to soak the entire pot in a basin for about 15 minutes, then let it drain fully before putting it back.

But perhaps the single most helpful tool you can invest in is a good-quality mist sprayer — one that holds at least a litre and has a proper trigger. Use it generously, twice a day if you can, so that the leaves glisten and drip with moisture.

Just bear in mind that high humidity can affect furniture and surfaces, so choose your locations wisely. A kitchen or bathroom — where steam and splashes are already part of daily life — is often a better choice than a sitting room.

Mowing

I’m a firm believer in mowing as little as you can get away with. What that looks like will vary from garden to garden, but the truth is that long grass creates one of the richest habitats for wildlife you can have. And when it’s dotted with flowers — from bulbs, perennials, and annuals — it can be just as beautiful as any border.

Of course, not everyone agrees — especially those who value neatness above all, or children who want a space to run and play. So, for the sake of peace (and the lovely sound of children at play), it’s wise to keep a portion of lawn mown — a place to sprawl out, walk barefoot, or enjoy a picnic. But beyond that, try to keep mowing to a minimum. In our own garden, we’ve pared it back to just mowing paths through the long grass, which looks lovely and works well.

Whatever your approach to lawn care, don’t be tempted to cut it down to midsummer height right away. Start with the blades set high and just give the grass a gentle trim at first — more for tidying than shortening. As temperatures rise and growth kicks in, you can gradually lower the height, but always err on the longer side. Your lawn will thank you — it’ll be greener, thicker, and far more resilient.

And don’t forget to compost those clippings. Just be sure to mix them well with drier material like cardboard or straw — otherwise, you’ll end up with a soggy, smelly heap instead of beautiful compost.

Planting Out Sweet Peas

The best time to plant sweet peas into the garden is mid-April if you’re in the south, and a little later — towards the end of the month — if you’re further north.

Sweet peas love rich, moisture-retentive soil and prefer cool, temperate conditions — not frosty, but certainly not hot and dry. So the more organic matter you can dig in beforehand, whether compost or well-rotted manure, the happier they’ll be. I like to grow mine up a wigwam of hazel or bamboo sticks, but really, any sort of support will work — from sturdy canes to mesh or chicken wire.

I usually plant two or three sweet pea plants around each support and give them a really thorough watering before mulching generously. The mulch helps suppress weeds and, more importantly, keeps the roots cool and moist.

One tip worth noting: if you’ve bought a pot filled with lots of little seedlings, it’s better not to plant it whole. Gently split each pot into two or three smaller clumps and space them out at the base of the supports. That way, each plant has more room to grow without too much competition — and in the end, you’ll be rewarded with many more blooms.

Tidying Bulbs

While it can be tempting to trim back, tie up, or neaten the foliage of bulbs once they’ve finished flowering, it’s best to resist. Cutting back too soon will weaken the bulbs and reduce their display next spring.

However, there is a practical alternative. You can carefully lift the entire plant — bulb, roots, and foliage intact — and replant it into a pot. Place the pot in a sunny, out-of-the-way spot where the foliage can die back naturally and continue feeding the bulb, without leaving a tangle of yellowing leaves in your main garden display.

Once the foliage has fully died down, the bulbs can remain in the pot — just be sure they don’t get waterlogged. In fact, they’re fine to dry out completely. Come autumn, they’ll be ready to go back into the ground, rested and recharged for another year.

DEAD HEAD AZALEAS AND RHODODENDRONS

It’s a simple task, but one that’s often missed — and it can make a real difference. To prolong the blooming season of Rhododendrons and Azaleas, and to stop the plant from putting energy into making seeds, it’s worth deadheading the faded flowers — especially on the larger-flowered types.

Skip the secateurs, though. Using them can accidentally damage the delicate new buds forming just below the old blooms. Instead, gently hold the spent flower trusses between your finger and thumb and snap them off by hand.

Not only does this help prevent fungal problems, but it also encourages a better show of flowers next year. Plus, it tidies up the plant — removing those tired, brown blooms that can cling on long after their moment has passed.

PLANTING LILIES IN POTS

For one of the most beautiful and sweetly scented summer displays, plant lilies in pots. Most varieties prefer slightly acidic, ericaceous compost, though Madonna Lilies — among the earliest to bloom — actually thrive in alkaline conditions and can return reliably year after year if they’re happy.

The key to success lies in good drainage and a light, open compost. I like to mix in generous amounts of leaf mould and horticultural grit with a bark-based, all-purpose compost, though simply adding perlite or vermiculite will also improve structure and drainage.

When planting, set the scaly bulbs so they sit about four inches below the surface of the compost. Place the pots somewhere lightly shaded while they grow, and keep them well watered. Once the buds start forming in May or June, you can move them to their final spot.

As a general rule, lilies enjoy having their roots cool and shaded, while their flowers bask in the sun — so a sheltered position facing east or west usually suits them perfectly.

SUPPORTING HERBACEOUS PLANTS

Plant supports are all about prevention, not repair — so the ideal time to put them in place is before they’re actually needed. In a mixed border, the most effective approach is to set up a support system just as herbaceous plants begin to put on strong spring growth. Within a few short weeks, the plants will grow through and around the supports, which will quietly disappear from view while gently holding everything in place.

I rely on a combination of homemade metal frames, pea sticks (which are simply twiggy prunings from the garden), and the classic cane-and-twine method. Whatever materials you go with, try to think ahead — anticipate how the plant will grow and allow a bit of flexibility or adjustability in the structure. If it can also be pleasing to the eye, all the better. But most importantly, get your supports in early — it’s far easier than trying to rescue flopped or broken stems later in the season.

Seed Sowing

We should do all we can to cut down on the use of plastic in our gardens. A good first step is simply to reuse the plastic pots and seed trays you already have — and take care of them so they last for years rather than being replaced.

One of the simplest and most effective ways to avoid plastic altogether, especially when sowing hardy seeds, is to go back to an old, trusted method used by generations before us: the seed bed.

A seed bed is just a small patch of soil — even a metre or two is enough — where seeds are sown in neat, shallow rows. Once the seedlings are large enough to handle, they’re lifted and moved to their final growing spots.

It’s a low-impact, low-cost approach that needs no extra materials, no bought compost, very little watering, and hardly any fuss. Best of all, it produces strong, healthy plants. That’s because from the very beginning, the seedlings grow in real soil, forming natural relationships with the microbes and fungi that support plant health and resilience.

When it’s time to transplant, just lift a small clump with a trowel, keeping plenty of soil around the roots. Water them in well, and they’ll carry on growing without much stress from the move.

To prepare your seed bed, work the soil until it’s crumbly and fine — something you can sift through your fingers — then rake it level and sow in short rows, making sure to label them clearly. Simple, traditional, and better for the planet.

SLUGS AND SNAILS

Slugs and snails often top the list of a gardener’s least-welcome visitors — and for good reason. They’re incredibly efficient at breaking down decaying plant matter, but unfortunately, they don’t distinguish between a rotting leaf and a tender new seedling.

Slugs tend to operate underground, thriving in damp, shaded soil. Snails, on the other hand, live above ground and tuck themselves into dark, dry spaces — cracks in old walls, gaps in paving, or the cozy shelter of a dense hedge. Container edges are another favorite haunt.

Though there are more than 30 species of slugs in the UK, only a few are truly troublesome in gardens. Interestingly, the largest slugs aren’t always the worst offenders. And what you spot above ground is just a glimpse — their numbers can exceed 250,000 per acre, most of them out of sight.

So, what can be done? First and foremost, avoid chemical slug pellets — they can harm birds, mammals, and other helpful creatures. Instead, create a small protected area like a cold frame or raised bench to start your young plants, and inspect it daily for unwelcome guests.

Feed your soil rather than your plants, and only as much as necessary. Overfeeding can lead to a flush of soft, lush growth — precisely what slugs crave. Try to grow your plants as robustly and naturally as possible, without over-pampering them or subjecting them to sudden changes.

And perhaps most importantly, make space for natural predators. In my garden, I’m fortunate to share the space with thrushes, frogs, toads, beetles, centipedes, shrews, and the occasional hedgehog — all of whom are enthusiastic slug hunters.

This does mean creating a wildlife-friendly garden: plenty of cover, no toxic treatments, and a willingness to accept a bit of nibbling here and there. It’s a small price to pay for a thriving, balanced ecosystem.

Plant new Potatoes

There’s no need to rush when it comes to planting maincrop potatoes — I’ve planted them as late as June and still had a perfectly decent harvest. But if you’re growing first earlies, the sooner they’re in the ground, the sooner you’ll get to enjoy that unbeatable, homegrown flavour that shop-bought potatoes just can’t match.

For traditional planting, dig a V-shaped trench about 6 to 9 inches deep, spacing the seed potatoes roughly 12 inches apart along the base. Once planted, backfill the trench so that the soil forms a ridge along the top. Be sure to leave about 3 feet between rows — this gives you space to earth up the plants later by mounding soil over the young shoots, which helps protect against late frosts.

I also like growing potatoes in raised beds, using a dibber to make holes about 6 inches deep. I plant each seed potato 18 inches apart in a grid pattern, which works well for smaller spaces. However you decide to plant them, one thing remains the same — potatoes thrive in rich soil, so dig in plenty of well-rotted manure or compost beforehand to give them the best possible start.

PRICK OUT TOMATOES

The right moment to prick out seedlings is when they develop their first true leaves — the ones that resemble the adult foliage of the plant, not the initial seed leaves. At this stage, the seedlings are ready for a little more space and nourishment.

Always handle them by a leaf, never the stem — damaging the stem is usually fatal, while a leaf can be replaced without lasting harm. Use a small spatula, dibber, or even a plant label to gently lift the seedling from the compost, trying to keep as much of the fine root system intact as possible — ideally with a little clump of soil still attached.

Transplant each one into its own small pot or plug tray — something compact, as large containers can hold too much moisture and risk waterlogging young roots. Use a slightly richer compost mix, perhaps with a bit of perlite for aeration and a handful of sieved garden compost if you have it to hand.

Once potted, return the seedlings to the greenhouse or a sheltered, frost-free spot and let them grow on steadily. By late May or early June, they’ll be strong enough to take their place in the garden.

SALADS

I love the variety of vegetables my garden produces, but nothing quite compares to the joy of a fresh salad made just moments after picking. There’s a crispness and vibrancy to just-harvested leaves that’s hard to beat — it’s the perfect mix of flavour, nourishment, and simplicity. Pair it with a soft omelette and some good bread and butter, and you’ve got a meal that feels luxurious in the most down-to-earth way.

Those salad leaves can come from all sorts of plants — tender baby kale, spinach, rocket, mizuna, mibuna, young chard, chicory, even pea shoots or the occasional raw broad bean. And that’s before you even consider vegetables we normally cook, many of which are delicious raw in salads too. That said, if you’ve got lettuce, you’ve always got the foundation for something fresh and satisfying.

Now is the perfect time to sow lettuce seeds directly into the soil. The ground is warming up, and quick growth is the secret to really good lettuce — tender, sweet, and full of flavour.

Lettuce prefers to germinate in cooler conditions and can actually stall if the soil gets too warm, particularly above 20°C. It thrives in nutrient-rich, well-drained soil and appreciates consistent moisture.

There are many different types of lettuce and even more varieties within each group. The key — as with all edible gardening — is to figure out what you enjoy eating and what grows well in your space. Then lean into that. Gardening always works best when you follow the path of least resistance — grow what thrives, and eat what you love.

LETTUCE

Lettuce is one of the easiest crops you can grow — and nothing beats the taste of freshly picked, homegrown leaves. The flavour and texture are far superior to anything you’ll find in a bag from the supermarket.

Most varieties take around 6 to 8 weeks to reach a good size for harvesting and will continue to produce for another few weeks if kept well-watered and cool. Lettuce thrives in mild, moist conditions, so a hot, dry spell can be just as challenging as a cold snap. Thankfully, many types will happily grow in partial shade, which can help keep them from overheating in summer.

The real trick to enjoying a steady supply — without having it all go to seed in a heatwave or ending up with too much at once — is succession sowing. That means sowing a small amount every 3 to 4 weeks. While one batch is being picked, another will be just coming into its own, and a third set of seedlings will be getting ready behind the scenes.

Sow thinly — a light hand with the seed will give you stronger, leafier plants than a dense cluster of seedlings fighting for space. As they grow, weed and thin carefully to a final spacing of at least 4 inches between plants. If you’ve got a greenhouse, it’s often best to sow into plug trays first — this gives young plants a head start and helps protect them from slugs when they’re most vulnerable.

For loose-leaf or cut-and-come-again types like Oak Leaf or Salad Bowl, you can scatter the seeds more freely and harvest by picking outer leaves as needed — the plants will regrow for several rounds of cutting. For heading types like Cos or Butterhead, sow them in rows with generous spacing so they have room to develop properly and can be kept tidy and weed-free until they’re ready to harvest one by one.