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10 February 2021

How to grow melons

A cool, sweet melon on a summer’s day is utterly delicious
Melons
CT
Ceri Thomas

Melons aren't the easiest fruit to grow in the UK, but you can have success in the greenhouse or outdoors in a sunny spot

How to grow melons: month by month

January February March April May June






SOW

PLANT
July August September October November December


HARVEST HARVEST HARVEST



Best melon varieties

Best Buy melons
What it looks like Variety name Yield from three plants
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7.8kg (nine melons)
We grew this charentais-type melon from seed. It was one of the first to produce ripe fruits and we harvested all nine melons in the last two weeks of August. We even had two melons from a single outdoor plant. We loved the sweet, perfumed taste and the soft, almost pulpy flesh, which was full of sticky, sugary juice. The rind is very thin, so there’s very little waste. It’s no surprise that it’s also an RHS AGM.
What it looks like Variety name Yield from three plants
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9.8kg (seven melons)
This galia melon was a Best Buy last time we tested melons as well and holds an RHS AGM. We grew it from seed and found it fared better than most at resisting powdery mildew, although we didn’t harvest any melons outside. Each polytunnel-grown plant produced two or three melons, which matured quite late in September. They weren’t quite as sweet as some of the other varieties, but they were still juicy and fresh-flavoured.
What it looks like Variety name Yield from three plants
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12.8kg (eight melons)
These grafted plants were some of the most robust in the test. Unfortunately, this variety isn’t available to grow from seed. The plants were less affected by powdery mildew than most and the melons steadily grew to be giants that were ready for picking in mid-September. Although the outside plants grew lots of melons, they didn’t ripen before the weather spoiled them. These charentais-type melons were utterly delicious – sweet, fragranced and tender.
What it looks like Variety name Yield from three plants
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9.6kg (11 melons)
We grew this variety both from seed and grafted plants. We found the seed-raised plants were healthier and gave us more melons than the grafted ones. We found it so easy to grow melons from seed that we don’t think it’s worth buying grafted plants, unless the variety is only available that way. This galia type was remarkable for the way the intense flavour lingered on our tongues. It’s juicy and had a firm but yielding texture.
What it looks like Variety name Yield from three plants
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10.4kg (seven melons)
This was one of the last melon varieties to ripen, with the last fruits hanging on until mid-October before they were finally ready. The plants were so badly affected by powdery mildew by then that we wondered if they would ever ripen. However, they did and were a prodigious size. Despite the promise of its name, our outside plants didn’t ripen. As a galia type, it doesn’t have much smell, but the very sweet, fresh taste is quite tropical.
What it looks like Variety name Yield from three plants
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7kg (11 melons)
We grew this charentais-type melon from grafted plants, and they were by far the most expensive in the test. However, we thought they were still well worth growing as the plants were robust and the melons were ripe by the end of August, so it had finished fruiting before powdery mildew took hold. The little melons were very sugary, and the flavour was perfumed and deep, but it had the freshness of a cucumber

How we test melons

We raised 12 melons from seed, including cantaloupe, charentais, galia and watermelon types. We also grew five varieties from grafted plants, including one variety, ‘Esmerelda’, which we grew from both grafted plants and seed. In late April, our plants arrived and we sowed our seeds using a Best Buy compost for sowing seeds. We kept the module trays on a heated bench until they germinated. We potted on our plants as they grew and planted them in 15L containers when they were around 15cm tall in late May, using a Best Buy compost for containers and a Best Buy controlled-release feed. We grew three plants of each variety in our polytunnel, with one of each variety trailing over the greenhouse bench and the rest trained up bamboo wigwams. We removed excess sideshoots, fruits and flowers, so only four fruits matured per plant. Spare plants were grown outside in a bed through a sheet of weed-suppressing membrane. We watered them at least once a day and liquid-fed them weekly from late August when the controlled-release feed was running low. Despite being regularly watered and fed, all of our plants suffered from powdery mildew. We picked the fruit from late August, and checked the fruits daily to harvest and taste at the optimum time.

When to sow

In mid to late April, sow seeds in modules or small pots, using a Best Buy compost for sowing seeds. They need to be kept between 18°C and 21°C to germinate, so place them in a heated propagator or on a sunny windowsill. Keep the compost moist, but not wet. Pot on when the first two true leaves have appeared, using a Best Buy compost for raising young plants.

Caring for your plants

Planting

Melons are tender, so they’re best grown in a greenhouse, polytunnel and under a cloche. Plant in a large pot in Best Buy compost for containers that’s mixed with a Best Buy controlled release fertiliser. If you want to grow outside, we found that growing melons through thick black plastic doubles the crop. Harden off before planting out once all chance of frost has passed. Plant in their final position once the plants reach around15cm in height.

Pinching out 

Pinch out the main growing point after five leaves have formed. Choose the best four side-shoots that develop and remove all others. When four fruits are gooseberry-sized, remove all other fruits and flowers. Provide plenty of room for them to grow. They scramble up supports such as netting.

Watering and feeding

Water plants at least once a day, more frequently in hot weather. Start feeding weekly with tomato feed in mid-August when the controlled-release feed added to the compost starts to run out of steam.

How and when to harvest

Harvest in: August to October

Harvest as soon as the melons are ripe. Smell them regularly to determine when they have developed their sugars. A ripe melon has a slightly soft end, so feel them and harvest as soon as they are soft enough.

Common growing problems

Powdery mildew

Powdery mildew is a fungal disease that thrives in high humidity and where there is little air flow, so greenhouses and polytunnels provide perfect conditions for its spread. Melons are particularly susceptible. The first appearance is as a sprinkling of white on the top surface of the leaves. This will quickly spread to cover the leaves and is followed by beige patches where the leaves are dying. It can affect all parts of the plant, including the stem and fruits. There are no fungicides for edible plants, so you have to control it by reducing humidity levels. Open the greenhouse vents and door, and put up shading. This reduces the temperature in the greenhouse and, as a result, the humidity level goes down too.

Read more about powdery mildew.

Red spider mite

Glasshouse red spider mite sucks the leaves, leaving mottled, pale patches covered in webbing. Control with biological controls, such as Phytoseiulus persimilis or amblyseius.

Read more about red spider mite.

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