· Brooks Wilson's Answer
· Hi Ashley,
Irregular watering patterns or heavy rains just before watermelons ripen can cause them to split while still on the vine.
Water watermelons heavily on a once a week basis. Make sure to water enough to soak down deeper in to the soil. Apply at least an inch or two of water each time. Watermelons are deep rooting plants and if watered only at the surface during drought times, will not root deeply. If Watermelons are not watered properly when the fruits are young they may develop blossom end rot or may result in immature or malformed fruit. Blossom end rot is caused by calcium deficiency. Proper watering levels will allow the watermelon plants to absorb calcium.
Do not water Watermelons daily. Watermelons do best in dry hot weather. Infrequent watering, one good soaking a week, is the best way to promote deep rooting. Watermelon roots reach far into the soil, which makes them a drought-resistant fruit. Watermelons do best in dry and warm weather. After the watermelon plants are established they can go for weeks without watering.
Mulching plants is also a good idea. Mulching prevents weeds and conserves moisture during drought periods. Apply mulch before watermelons appear. Hay, straw, or crushed leaves are the preferred mulches. Pile mulch about 4-6 inches deep over the entire Watermelon plot and around the base of each plant as well. Watermelons consume a lot of soil nutrients. Compost mulch helps supply additional nutrients. A good time to mulch is when the ground is warm and the soil recently soaked by irrigation or rainfall.
Many areas of the country have experienced drought this season (2012) and are now experiencing heavy rainfall. If this is the case in your area, it very well may be why the watermelons are splitting.
Hope this helps you out.