How to grow melons

Melon seeds are widely available in garden centres and from online seed suppliers. There are biosecurity risks associated with growing from the seed of supermarket-bought fruit, so this should be avoided.

Young plants may also be available in spring and early summer, from the same sources, although the choice of varieties will be limited. Grafted melon plants are also available from some online fruit and veg suppliers by mail order. Buying young plants is a good option if you only want one or two plants, or don’t have enough space, time or sufficiently warm conditions to germinate seeds and raise young plants yourself. 

• You can plant melons in a large container, growing bag, greenhouse border, or large coldframe, from late May onwards, once the temperature stays reliably above 12–15°C (54–59°F)  
• Containers should ideally be at least 40cm (16in) wide and deep, filled with peat-free multi-purpose potting compost. Position one plant in the centre of the container  
• You can grow one melon plant in a standard growing bag 
• Before planting in a greenhouse border, add up to two bucketfuls of well-rotted organic matter, such as garden compost, per square yard/metre. Space plants 45cm (18in) apart at the base of supports

• Harden off melon plants carefully in a coldframe, mini-greenhouse or under cloches before planting out from early June, once you’re sure temperatures won’t drop below 12–15°C (54–59°F) at night
• Choose a very warm, sunny and sheltered planting site with fertile, free-draining soil 
• Prepare each growing site by digging in two bucketfuls of well-rotted organic matter. Ideally do this a few weeks before planting, to allow the soil to settle. Alternatively, if you're practising no-dig, mulch the surface of the soil ahead of planting directly into the mulch 
• If possible, warm the soil for several weeks ahead of planting by covering it with cloches or biodegradable or re-used fleece
• Space plants at least 90cm (3ft) apart if trailing, and 45cm (18in) apart if growing up supports
• You could also try planting in large containers at least 40cm (16in) wide and deep, positioned in a very warm, sunny courtyard or patio

Melons can either be grown up supports or allowed to trail on the ground. Growing them vertically means they take up little ground space, which is particularly useful in a greenhouse. Suitable supports include sturdy bamboo canes, netting, vertical strings or trellis, which their tendrils can twine around. Melons can make large plants and mature fruits are heavy, so make sure the supports are strong and well anchored.

Decide how you want to train the stems from the start – there are several options. When growing vertically, you can have one main stem growing up the support, then train the side-shoots horizontally and pinch out the tips after seven to nine leaves have formed, to encourage flowering shoots to develop. Alternatively, once the young plant has five leaves, you can pinch out the growing tip to encourage side-shoots. When these appear, keep the four strongest and remove any others. These shoots can then be grown up supports or can trail on the ground. If growing in a large coldframe, arrange the four shoots in an X-shape. If growing under a long tunnel cloche, send two shoots in each direction.

Aim to keep the soil or potting compost evenly moist but not saturated. When watering, avoid wetting the leaves, as that can encourage fungal diseases. Use rainwater from a butt whenever possible, and water at cooler times of the day, ideally in the morning.

Melon plants grown undercover should be watered regularly, especially when fruits are forming. During hot spells, they may need watering daily.

Outdoor plants growing in the ground should need less regular attention, especially if you mulch the soil, but will still need watering in dry weather in order to grow and crop well.
 

Lay a 5-7.5cm (2-3in) layer of mulch over the soil around the base of melon plants to help hold moisture in the ground, reduce the need for watering, and deter weed germination. Use well-rotted organic matter, such as home-made garden compost. Leave a gap around the base of the stem to help prevent rotting.
  

Stop feeding and reduce watering when the fruits start to ripen and the foliage dies back in late summer.

Melons are primarily insect-pollinated, with bees serving as key pollinators. Opening up tunnel cloches, coldframes and greenhouse doors and vents during the day allows pollinating insects access to flowers. However, bear in mind that once the first fruit starts to form, this can inhibit further fruit formation – to avoid this, you could wait until the plant is in full flower, then ventilate to allow insects in. 

When growing under cover, pollination can be poor even with vents open, so it’s often best to hand pollinate as well. Melons produce separate male and female flowers, so you need to transfer pollen from a male flower to a female flower for a fruit to develop. It’s easy to recognise a female flower, as it has a small fruitlet behind it, while male flowers do not. Pick off a fully open male flower and carefully remove the petals to expose the pollen-bearing anthers. Then gently press the male flower into the centre of open female flowers – one male flower will pollinate several female flowers. Alternatively, you can use a small paint brush to transfer the pollen – gently dab the pollen from the centre of a male flower into the centre of up to four female flowers.