What To Plant In Your Polytunnel or Greenhouse in April

Spring seedlingsThis month in your polytunnel or greenhouse, watering is key. You will find that though it may still be too cool to sit for long outside for most of the month, inside the polytunnel on a sunny day things are really starting to heat up. Make sure you open doors and consider ventilation as it is important even now, this early in the year. This is the month when you really switch over from growing slow-growing winter greens to the full-fledged joyous growth of the spring.

Peas and broad beans that over-wintered in your polytunnel or greenhouse will begin to grow rapidly this month, as will any greens that are on the go. Remember to thin carrots, beetroot and any other under-cover crops that need it and keep on top of weeds to stop things from getting out of hand. Continue to successional sow your favourite crops so you will have a near continuous supply. You may have some new potatoes under cover if you have the space. Towards the end of this month, it will be time to earth them up so as to maximise your yield.

This month, the polytunnel can take over from your windowsills indoors as a seedling growing area. You can sow a wide variety of seeds this month that can be potted up in your polytunnel or greenhouse and then planted out after the last frost date in your area. For example members of the brassica family, carrots, turnips, spring onions, and plenty of other crops that can be grown outside or under cover. Before the summer season arrives and your covered-space fills rapidly, make sure you have all the structures, framework, staging and supports that you will need in place, as it is nigh on impossible to place things without damaging anything once your plants take over the space.

French beans, courgettes, summer squash and cucumbers can also now be sown for planting under cover. Get these started now indoors and place them in their final growing positions as soon as the weather warms up. Hold off placing tomatoes and peppers that have been grown indoors from seed in an unheated covered space for another month or so as they really need the heat of very late spring and early summer.


If you have had crops in your polytunnel over the winter then you should still be getting some food to see you through the 'hungry gap' and harvesting winter cabbages, spinach, and winter lettuces. As you clear out previous crops to make way for the new, make sure to amend the soil with the addition of some good quality, organic compost to ensure that you can continue to grow prolific and healthy crops throughout the year.