- Zucchini plants grow only when temperatures remain above 32 Fahrenheit and lose vigor if temperatures exceed 95 degrees Fahrenheit for long periods of time. In a garden setting, expect zucchini plants to live for three to four months when temperatures fluctuate within the 60 to 90 degree range. Plants may live longer if temperatures are cool--40 to 65 degrees--growth is slow and flowering and fruiting are delayed, sparse or never occur. Fall frost or summer heat and drought kills zucchini plants, as can bouts with hungry insect pests or a fungal disease.
- Extend the life and productivity of zucchini plants by promptly harvesting fruits. Depending on plant cultivar, a zucchini plant begins to produce small immature fruits worthy of picking in as little as 50 days after sowing seed. Biologically, a zucchini plant's ultimate goal is to reproduce seeds to ensure the species can exist for another generation. By picking fruits, the plant's hormonal balance indicates that no seeds have yet been made. The response by the plant is to continue flowering in an effort to produce fruits with mature, viable seeds.
- Regional climate can affect how long a zucchini plant ultimately endures. In the northern half of the United States, zucchini grows only from spring to fall when frosts don't occur--generally from May to October. In southern parts of the country, especially in subtropical Southern California, the low deserts of Arizona, Southern Texas and peninsular Florida, winters may be frost-free and the summers long and oppressively hot. In these areas zucchini is grown from late summer to late spring to avoid the most inhospitable summer conditions of brutal heat, drought or excessive humidity.
- For the longest, most productive zucchini plants, sow seeds in fertile, crumbly, near-neutral pH soil rich in organic matter. Full sun is needed for good leafy growth and flowering. Keep the garden patch free of weeds. Maintain an evenly moist soil, never too dry nor soggy or flooded. Various insects eat zucchini plants, including borers, beetles and cutworms, all of which can kill plants or cause withering. Diseases remain in soil and are particularly abundant in areas where other vining crops grew the previous two years. Therefore, don't plant zucchini where cucumbers, pumpkins or melons have grown.