Key Takeaways
Fertilize fall veggies in late summer, but stop once autumn fully sets in.Add compost in the fall to enrich the soil and prep it for next year’s crops.Skip fertilizing perennials, trees, and shrubs to avoid frost-damaged growth.
You’ve fertilized your vegetable garden throughout the spring and summer, and you’ve been rewarded with an abundant harvest. But as summer winds down and transitions into fall, should you still keep feeding those veggies with the occasional dose of fertilizer?
It’s a good question to ask—not least because the answer varies depending on where you live and what’s growing in your garden. Here’s what the experts say about whether you should fertilize vegetables and other plants in the fall.
Meet the Expert
Amanda Staples is the owner and farmer at Germantown Kitchen Garden, an urban farm and plant nursery in Philadelphia.
Leslie Halleck is a horticulturist and green industry business consultant at Halleck Horticultural in Dallas.
Why You Should Fertilize Fall Vegetables
According to Amanda Staples, owner and farmer at Germantown Kitchen Garden in Philadelphia, fertilizing in late summer can actually help vegetable crops.
She recommends adding compost or an organic fertilizer to the soil surface around vegetable seedlings, particularly if you’re planting cool-season crops after other veggies planted in spring or summer.
Exactly when you should stop fertilizing vegetables in the fall, though, depends on your region’s climate and which crops you’ve planted.
“Warm-season vegetables such as tomatoes, peppers, and beans will produce harvests up until a few weeks before the first frost date, but sometimes up to the first hard frost—especially in warm to hot climates,” says Leslie Halleck, horticulturist and green industry business consultant at Halleck Horticultural in Dallas.
Depending on which growing zone you’re in, those summer veggies could continue putting out fruit until mid- or late November.
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When to Stop Fertilizing Vegetables in Fall
Halleck says you can fertilize veggies up until about two weeks before your first hard frost date, or when you plan to collect your last harvest and pull the plants
“If you live in a cold climate, your first hard frost date or last harvest will likely be in early fall, so simply adjust your timing accordingly,” Halleck shares.
Staples agrees that it’s okay to continue feeding vegetable plants into fall, but the type of fertilizer you choose plays an important role.
“If you find that your fruiting crops like tomatoes, peppers, and eggplant are petering out, water with a liquid fertilizer that’s high in phosphorus and low in nitrogen to promote flowers and fruit rather than green growth, or leave them be,” she says.
Halleck notes that the rules are a little different for gardeners in hot and mild climates, where it’s possible to cultivate cool-season vegetables like brassicas, salad greens, and root veggies year-round.
“As these crops are frost-hardy in such climates, are actively growing, and are typically heavy feeders, you’ll fertilize fall through winter and into early spring,” she says. “If you’re growing any vegetables in a greenhouse, you’ll continue fertilizing all through winter as needed, as long as ideal growing conditions are present.”
Why You Shouldn’t Fertilize Perennials in Fall
While it’s a good idea to fertilize annual vegetables in the fall, you’ll want to avoid doing this for perennial plantings in your garden.
“Fertilizing perennial crops in the fall is discouraged because fertilizer will encourage the plant to put on new growth, which you don’t want so close to winter,” says Staples. “We want our perennials to be fortified against harsher weather.”
Halleck agrees, noting that for perennials, trees, and shrubs, you’ll want to stop fertilizing four to eight weeks before your growing zone’s last frost date. Instead, wait to fertilize perennials until late winter or early spring, when these plants are putting out their very first new growth of the year.
The added nutrition will give them an energy boost when they need it most and support healthy, vigorous growth in the spring and summer.
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