The pre-cooling technique is hardly used in the storage of watermelons; in case they are subject to this technique, the temperature must be over 7ºC, so as to avoid the fruit damage.

The watermelon is quite sensitive to cold temperatures and they may be damaged at temperatures below 4.5-10ºC. However, if they are put under high temperatures before their cold storage, they bear much better the low temperatures. For instance, it has been proved that watermelons which have been kept for 4 days at 26ºC are later on stored at 0ºC for 12 days without any damage. If they are not subject to this pre-treatment, they last only for 4 days.

Watermelons cannot be preserved for more than 2-3 weeks. In optimal conditions and for very carefully handled fruit, they may last for2-3 months, although they loose flavour quality. The optimal conditions are at temperature between 2 and 10ºC and 80-95% of relative humidity. If they are marketed within two weeks, they are stored at 13-16ºC. For longer storage periods, the fruit is put in perforated plastic bags or covered with waxen paper.

Watermelons are sensitive to ethylene, so they must not be transported or stored with produce giving off this gas. If so, the fruit looses the pulp’s red colour, it softens and gives off bad smells.

The transport must last at the most between 14 and 21 days. The optimal temperature is 10ºC, and the moisture level must be between 85 and 90%.

Watermelons may be affected by several problems during their storage, like diseases produced by fungi and bacteria, chilling injuries or excess of ethylene in the storage room.

Chilling injuries: they occur at temperatures below 4ºC; they are characterised by brown spots in the rind and a bad taste. The low temperatures cause the loss of the pulp’s red colour.

Damages caused by ethylene: watermelons are sensitive to ethylene; if they are stored together with this gas they undergo several alterations like loss of firmness and thickness of the rind, reducing their quality in great extent.

Diseases: watermelons may be attacked by diverse fungi or bacteria during their storage. The main entry point is the peduncle area; therefore, it is important to keep a small piece of stem in order to avoid the micro-organisms penetrating through the wound.