Pumpkin

A pumpkin plant is not a compact garden citizen. A single vine of a large variety can spread fifty to a hundred square feet by midsummer, and most gardeners plant pumpkins far too close together — three feet apart when they need ten or twelve. The result is a tangle of overlapping leaves where air doesn't move and powdery mildew spreads from leaf to leaf until the whole planting is a mass of white-dusted foliage by late August.

The other common mistake is planting into cold soil. Pumpkin seeds sown before the soil reaches at least sixty degrees tend to rot before they germinate, and even if they do come up, the roots develop poorly in cold conditions. Wait until at least one week after your last frost date — longer if the spring has been cool — and plant on raised hills or mounds to warm the soil faster and improve drainage. The hills should be about twelve inches high and eighteen inches across, enriched with compost or aged manure.

Not all pumpkins are the same plant. The large carving types — Howden, Atlantic Giant, the orange globes that appear on every October porch — tend to be mostly water and stringy flesh, bred for size and shelf life rather than flavor. They make poor pies. Sugar pie types and heirloom varieties like Long Island Cheese have denser, sweeter flesh and are what you want if you plan to cook the harvest. Decide which kind you're growing before you buy seed; the cultural requirements are similar, but the end use is entirely different.

Pumpkins are heavy feeders and benefit from side-dressing with compost or a balanced fertilizer once the vines start to run. Water deeply but not frequently — the goal is to encourage deep root growth rather than keeping the soil surface constantly damp, which invites fungal problems. Mulch around the base of the plant once it's established to conserve moisture and suppress weeds.

Powdery mildew is nearly inevitable on pumpkin vines by late summer, especially in humid climates. The white coating on the leaves doesn't kill the plant outright, but it does slow photosynthesis and can reduce fruit size. Spacing plants generously, watering at the base rather than overhead, and removing the most heavily infected leaves can slow the progression. Some gardeners accept that powdery mildew is part of growing pumpkins and plan around it — the fruit usually matures before the foliage collapses entirely.

Harvest when the skin is hard enough that you can't dent it with a thumbnail, and leave several inches of stem attached — pumpkins without stems rot quickly in storage. A light frost won't hurt a mature pumpkin, but anything harder than that can damage the skin and shorten storage life. Cure them in a warm, dry place for a week or two before moving them to cooler storage.