April Growing Guide

Premier team

Gardening in April: Our top tips for growing, sowing, and maintenance

April Growing Guide for PolytunnelsTransport your garden to warmer climates by growing under cover this month. Whether you place your seedlings under a polytunnel or a sturdy garden cloche, with April showers and late frosts, keeping your crops protected is essential.

Once you've set up and installed your equipment, knowing which seeds to plant could help you to grow successfully throughout spring and summer too. To find out what to sow in April, along with some of our very own gardening tips, read on.

Seeds to plant in your polytunnel in April


Pumpkins are a thrilling choice for a family project, especially if you want to share the experience with young children. Pumpkin seeds sown in April should be ready for harvest in September and October, perfect for Halloween. Just give them a warm position with plenty of sunlight, water, and shelter from winds.


Homegrown courgettes are much more interesting than their shop-bought counterparts. Not only do they vary in shape, colour, and texture – giving them a special sort of character – but they're also easy to grow and produce in abundance. In good weather, you might even expect to pick between three or four courgettes each week, making them a great choice for planting in April.

Butternut squash

Squashes are best sown and planted indoors or in a polytunnel, but they can be moved outside under the cover of a fruit and vegetable cage after the last frost. Sow them indoors from mid to late April, although they can also be sown outdoors from late May. Once sown, cover your growing area with a cloche for as long as possible after germination before thinning the seedlings. Gardening in April provides wonderful opportunities for delicious autumnal harvests, and planting squash makes no exception.


The joy of growing your own tomatoes in spring promises a delicious reward through summer. Tomato plants are best suited to growing in containers, either on a sunny windowsill or pride of place in your polytunnel. From tiny, vibrant cherry tomatoes to larger, juicy beef tomatoes, you'll have plenty of varieties for late summer salads and sandwiches.


Celery is a staple ingredient not only for cool, refreshing salads but also makes up an essential part of the base for many Mediterranean-influenced dishes. Sown between mid-March and early April, celery plants cope best in trays, pots, or modules of moist compost. Water generously throughout the season to make sure your seedlings are ready for planting from May.

Flowers to plant in April

If you're looking for bulbs to plant and seeds to sow in April, creating a new meadow-like area in your garden could be a fantastic project for the month. As the weather gets milder towards the end of April, hanging baskets could be hung up in preparation for the summer.

However, the entire month of April is a brilliant time to plant hardy annuals including:

  1. Sunflowers
  2. 'Poached egg' plant
  3. Viper's-bugloss
  4. Potted marigold
  5. Pansies

When a bit of free space becomes available in your polytunnel or greenhouse, you can start to plant last year's tender perennial cuttings along with summer-flowering bulbs like dahlias, lilies, and gladioli.

How to maintain your garden in April

1. Ventilate your polytunnel
With warmer days on the horizon, it's time to prepare your plants for milder nights too. Temperatures can soar under cover in spring, so it is important to ventilate the polytunnel as much as possible. You can achieve this easily by opening doors and ventilation screens on warm days. As the days get longer, sunlight hours also increase – so it's important to check the temperature inside your polytunnel as frequently as you check the weather forecast.

2. Water frequently
Despite April being known for heavy rain showers, one of our best April gardening tips is to water your indoor and outdoor plants carefully. This month is also the best time to start gradually increasing the volume of water given to houseplants and garden plants, especially those in containers.

Equally, make sure you know how to spot signs of overwatering for each type of plant you're growing. Our specialist polytunnel gutters can make sure that any excess water is sufficiently drained away from your polytunnel roof – and harvested into a water butt for use in your garden during dry spells.

3. Protect tender plants
Occasionally, frost can set in overnight during the first weeks of April. On colder nights, make sure you protect delicate plants with a garden cloche or fleece. If you haven't got the space to install a new protective structure, you could try a temporary solution like newspaper to keep overnight frost at bay.

4. Keep pests at bay
Even though the risk of contamination from pests won't peak until midsummer, it's crucial to protect your plants from hazardous critters with netting. Watch out for greenfly and other pests, especially on plants received from commercial companies or fellow gardeners.

If possible, keep these separate from the plants you've already raised for at least a couple of weeks – almost like a quarantine period. Tip out potted plants occasionally and check for grubs that might have settled among the roots.

5. Free up growing space
Lastly, April is one of the best months to clear away older, overwintered crops and make space for summer plantings. Additionally, fresh compost can be used in your planters to fill the borders of your polytunnel, ready for sunnier days. If you're struggling to decide what to grow in April, clearing space makes a productive activity in the meantime.

Top Tips

If you're growing tomato plants this year, move the seedlings into larger containers whenever the roots reach the outside of the pot to give them more space.

Keep an eye on chilli plants sown earlier in the year and pinch out the tips of the plants to encourage bushy growth and more fruits over the growing season.

Feed strawberry plants in pots and help flowers to set by pollinating by hand - moving the pollen from flower to flower by hand or with a soft brush.

We can help with polytunnel growing all year

At Premier Polytunnels, we've been helping professionals and beginners with their gardens for over 35 years. With our unrivalled industry expertise, we're on hand to help you make the most of your harvest through every season.

If you'd like to create an environment that naturally promotes healthy growth throughout the year, browse our range of high-quality polytunnels online. We know that finding the right equipment can feel tricky, so if you have any questions or you'd just like a second opinion, don't hesitate to get in touch. You can give us a ring or send us an email and one of our friendly team members will be happy to assist you.