Heat Loving Plants Q&A

Growing Heat Loving Plants in New York

By Pat Curran, Horticulture Educator, Tompkins County Cooperative Extension

Question: Summers here can be cool. How can I get winter squash and melons to produce?

Upstate New York is not the ideal place to grow heat-loving eggplant, winter squash, and melons. Our growing season is typically about 135 days, from the average last frost of May 14, to the average first frost of Oct. 1, but not all those days are very warm! Early June can be cool, and days get shorter and evenings get cooler in late August.

Most of the heat-loving crops need to be started early, so visit local nurseries and garden center for healthy-looking transplants (these should have dark green foliage and be short and stocky, rather than tall and spindly). The soil should be covered with black plastic to warm it up, while you're shopping for plants. Make slits in the black plastic, and plant the transplants a little deeper than they are in the pot or the cellpak, especially if they are a little 'leggy.' Plan to use commercial row cover over the plants. Besides protecting from insects such as cucumber beetle or flea beetle, which attack squash or melons, and eggplants respectively, the row cover will help to accumulate heat and protect from cool breezes. The black plastic mulch helps warm the soil, and can make the difference for heat-loving crops. Some gardeners position rocks nearby to absorb and later release heat.

The plants may not look much different for a couple of weeks, because they are growing the root systems needed to support top growth. Keep them watered if there isn't enough rain. Rowcover can be left on these heat-loving crops for several weeks, depending on the season and the temperature, but it will need to be removed to allow pollination when the flowers appear.

The GrowLine horticultural hotline sometimes receives calls from gardeners whose squash or melons haven't set fruit, despite flowering. Squash and melons have separate sexed flowers. The earliest flowers, which are male, cannot produce fruit. Female flowers can be distinguished by the swelling at the base, which develops into the fruit after pollination and fertilization. If female flowers are dropping off, the problem may be lack of pollination. Perhaps there is a shortage of bees, or maybe they haven't been out flying due to the weather. Planting flowers nearby can help attract bees. However, hand pollination of female flowers can be done with a Q-tip or a small brush.

After some fruits are developing, trim the tips of the squash or melon vines to prevent the plants from setting fruit that will not have time to mature before frost. Try putting a rock under each melon to keep it dry and make mouse damage less likely. Watch the weather forecasts while your butternut winter squash slowly changes from pale green to a nice tan color. Be ready with covers as the first frost approaches!

For more information about gardening, including growing heat-loving plants, consult the Cornell gardening website, fruit section, or call the horticultural hotline at Cornell Cooperative Extension of Tompkins County at 272-2292.

Last updated January 29, 2021