Melon Growing Calendar: Every Stage from Sowing to the First Slip

The shape of a melon season

A melon takes roughly three and a half to four months from sowing to the first fruit slipping off the vine, and almost all of it has to be warm. The season falls into five unequal parts: three or four weeks raising the plants, a month of building the vine, a short and busy fortnight of flowering and fruit set, six or seven weeks of filling during which you mostly stay out of the way, and a final ten to fourteen days of ripening in which what you do about water decides the flavor.

Three decisions shape the whole thing and all of them are made in the first half. When you plant out, which is governed by soil temperature and not by the calendar; when you pinch the main shoot, which is what starts the crop; and how many fruit you let each plant keep. Everything else is maintenance, and maintenance rarely rescues a season in which those three were wrong.

Raising the plants and getting them out

Sow three to four weeks before you expect to plant out and not a day earlier, into individual pots rather than a tray, at 80 to 85F (27 to 29C). Move the pots into the brightest place you have the moment shoots appear, because warmth without light produces long weak seedlings within days. Harden them off over about a week before they go out.

Then wait for the soil. Push a thermometer four inches (10 cm) down at mid morning for three consecutive days and take the lowest reading; plant only above 65F (18C). If your climate makes that a long wait, do not plant early, warm the ground instead: black plastic laid over the bed two to three weeks ahead lifts the soil several degrees and is the single most effective thing available in a cool summer.

1. Sow warm, in individual pots One or two seeds per three inch (8 cm) pot, half an inch (1 cm) deep, on a heat mat or in the warmest spot in the house. Thin with scissors at the first true leaf.
2. Warm the bed while they grow Lay black plastic over the planting bed two to three weeks before planting and plant through a cross cut in it. The mulch then suppresses weeds and stops soil splash all season.
3. Plant on a raised hill Set plants on a hill eight to twelve inches (20 to 30 cm) above the surrounding ground, rootball level with the surface, never buried. The hill drains and warms, and it prevents collar rot.
4. Cover for the first fortnight A cloche or row cover protects against wind and cold nights while the roots move out. Take it off the day the first flowers open.

Building the vine, and the pinch that starts the crop

For the first month after planting the whole job is growing a big healthy plant. Male flowers will appear during this period and that is normal; if the occasional early female sets while the plant is still small, remove it, because a fruit carried on a small plant either aborts or fills poorly and costs the growth you need either way.

The key job in this window is pinching out the tip of the main shoot at five or six true leaves, which pushes the plant into the laterals that carry the female flowers. A week or two later, select three or four strong laterals, remove the rest while they are small, and lay the keepers out like the spokes of a wheel. Feed once with a balanced fertilizer about three weeks after planting and keep nitrogen moderate: a plant fed hard now makes leaves instead of melons.

1. Pinch the main shoot at five or six leaves This is what starts the crop. Do it on a dry morning so the wound seals before evening rather than taking up infection.
2. Select laterals a week or two later Keep three or four strong, evenly spaced shoots and rub the rest out while they are an inch or two long.
3. Feed once at three weeks About 2 oz (60 g) of a balanced fertilizer per plant, scattered around and watered in. Do not repeat until fruit have set.
4. Remove very early fruit Pinch off any female flower that sets while the plant is still small. Building the vine now buys larger fruit later.

Flowering, setting and labeling

The flowering fortnight is short and it is the busiest part of the season. Male flowers open first and the females follow, each on side shoots, each open for a single morning. Insects do most of the work, so take covers off, avoid spraying anything while flowers are open, and have other flowering plants nearby. In poor weather, or under cover, transfer pollen yourself before nine in the morning with a fresh male flower, covering the whole stigma.

Label every fruit as it sets, with the date, on a marker pushed into the soil beside it. Six weeks later that number is the backbone of the harvest decision and nothing else records it. Once the leaders reach tennis ball size, thin to the two or three best fruit per plant and take the rest off the bed, then stop each fruiting shoot two or three leaves past its fruit.

1. Uncover at the first flower Any row cover comes off the day flowers open, without exception, or nothing gets pollinated and the plant sets nothing at all.
2. Never spray open flowers Insecticide applied to open flowers costs you pollinator visits for days. If something must be sprayed, do it in the evening once the flowers have closed.
3. Write the date on a label Push a labeled marker into the ground beside each fruit the same morning it sets. You will not reconstruct it later.
4. Thin at tennis ball size Keep the two or three roundest and most advanced fruit, on different shoots, and cut the rest off. Fewer fruit means larger, sweeter melons.

Filling, then the last two weeks

Through the filling weeks the plant wants steady deep water, a potassium rich feed every fortnight, and to be left alone otherwise. Erratic watering here is what causes split fruit and blossom end rot, neither of which can be fixed once it appears. Get a tile, board or thick straw pad under every fruit at fist size, keep the runners lying in one layer, and turn leaves over twice a week to catch mildew and mites early.

The last ten to fourteen days are different and they decide the flavor. Cut the water right back as each fruit approaches its day count, and stop feeding entirely. Water taken up at that stage dilutes sugars the leaves spent two months making, and a fruit finished dry is markedly sweeter than the same fruit watered to the day it slipped. Then check the stems every morning: the window between the first hairline crack and a fruit split on the ground is only a few days in warm weather.

Stop nitrogen entirely once fruit are filling. Late nitrogen puts the plant back into leaf growth and the fruit finish pale, late and bland.

Closing the season and carrying it forward

When the last fruit is off, clear the bed completely rather than letting the vines die back in place. Cucurbit diseases overwinter in that debris more reliably than anywhere else, and a bed cleared at the end of the season is a bed that starts clean. Never compost a plant that wilted, and note which bed grew melons so no cucurbit returns to it for at least three years.

Then write the season down while it is fresh, because five numbers are worth more than any amount of general impression: the planting-out date and the soil temperature that day, the date you pinched the main shoot, the pollination date and slip date for each fruit, how many fruit you kept per plant, and whether the flesh was underripe, right or watery. Two seasons of those figures give you a melon calendar for your own garden that no general guide can supply.

1. Clear every scrap Take vines, leaves and unpicked fruit off the plot. Anything left is next year's mildew source and overwintering habitat for beetles.
2. Record your real day count Days from pollination to slip, for each fruit, plus what the flesh was actually like. Your own number beats any published range.
3. Record fruit kept against flavor Two fruit on one plant and four on the next, in the same bed, settles the thinning question for your conditions in a single season.
4. Note the bed for the rotation Write down which bed grew melons. Three years without any cucurbit in that ground is what keeps fusarium out of the next crop.