A watermelon that impresses at first sight: an unusually elongated and narrow shape, light green rind with veins and red flesh in fruits that can reach 18 kg.
About the variety. 'Charleston Gray' is a semi-early variety with a very distinctive, narrow elliptical shape. Fruits weigh between 12 and 18 kg, with a light green rind and red flesh. The flowers are edible and attract pollinators.
Itinerário técnico
Como cultivar watermelon charleston gray?
Um guia de cultivo passo a passo, da sementeira à colheita.
pH ideal 6.0 to 6.8Temperatura ideal 22 to 32 °CCompasso 50 cm in the row, 100 cm between rows
Sementeira
Sow in individual pots three to four weeks before planting out, two or three centimetres deep, with the compost between 25 °C and 30 °C. After pepper it is the seed that demands most heat to germinate: below 20 °C it simply will not come up. Transplant with the root ball intact, because the roots are unforgiving. Plant only once the soil is steadily above 18 °C. The first flowers are all male and set no fruit; if later the small fruits shrivel, pollination is failing: hand pollinate early in the morning with a brush. This variety makes long vines: the spacing given is for plants trained on a support or with the vines kept in check; left to run on the ground, it takes two to three metres.
Solo
It wants sandy or loamy soil, deep, very free draining and quick to warm, with a pH between 6.0 and 6.8. Enrich the planting hole with mature compost. In heavy cold soil the crop rarely pays; there, use a raised bed with a dark mulch.
Clima
It needs strong prolonged heat, between 22 °C and 32 °C, full sun and a season of three to four months without cold. It is the crop of choice for inland Portugal and Spain and southern France. On the cool Atlantic coast and in Germany it only pays under glass or in a tunnel, and even then with small early varieties. Inland in Portugal and Spain heat rather than cold is the limiting factor: in weeks above 35 °C the plant stalls and light shade over midday pays for itself. In France outdoor growing is reliable from the centre southwards, while in northern France and in Germany a greenhouse, a polytunnel or a warm south facing wall makes the difference, and planting out should wait until after the mid May cold snap.
Fertilização
Work two to three kilos of well rotted compost into each square metre before planting and add a handful of wood ash to top up potassium. Once growth is away, feed with a liquid organic fertiliser every two or three weeks, moving from a balanced formula to a higher potassium one as cropping begins. Avoid excess nitrogen, which gives lush leaves, a poor crop and a lot of aphids.
Rega
Water generously through growth and fruit fill and stop watering for the final two or three weeks. That is the golden rule for watermelon: water to the end means watery fruit with no sweetness and a tendency to split. Always water at the base, ideally by drip.
Controlo de Infestantes
The critical period is the first month, before the foliage covers the ground. Hand weed in that phase and, once the vines start to run, stop disturbing the soil: from then on the plant smothers weeds itself. A straw mulch under the foliage keeps the fruit clean and dry and greatly reduces losses to rot where fruit touches the soil.
Controlo de Pragas
The main pests are aphids, red spider mite, thrips and whitefly, and on young plants slugs and snails, which can cut down a newly emerged seedling in one night. Protect the seedlings with a cut bottle or an ash barrier for the first weeks. Against aphids and whitefly use potassium soap in the late afternoon; against red spider mite, which appears in dry heat, wet the leaves in the morning and use neem oil.
Doenças
Powdery mildew is practically unavoidable and shows as white dust on the upper leaf surface, above all from midsummer on. It is checked with potassium bicarbonate or sulphur applied at the first signs, together with removal of old leaves and good airflow. Cucurbit downy mildew gives angular yellow patches bounded by the veins and thrives in coastal humidity. Anthracnose and collar rot appear in waterlogged soil. Use a four year rotation and clear all crop debris at the end of the season, because that is where the fungi overwinter.
Colheita
Three signs together mark the point: the tendril nearest the fruit is dry and brown, the ground spot has gone from white to creamy yellow, and the sound when tapped is dull rather than metallic. Watermelon does not ripen after picking, so cutting too early is irreversible. Cut with a knife leaving a few centimetres of stalk. Allow about 70 to 80 days from transplanting to the first harvest of this variety. The reference colour is pale green skin with veining and red flesh, and that is what tells you it is ready.
