Vegetables to Plant in September

September denotes the end of summer for many gardeners and signals cool weather and incoming frosts in the fall season. Starting a garden in September may seem unwise, depending on your growing zone. Despite cold weather in the north, container gardeners and people in the south start looking for new vegetables to plant in September.

Although temperatures start dropping for most of the United States in late summer, many plants reach maturity in record time to begin growing in September. With select gardening tools to help retain soil warmth and fast-growing crops, it’s possible to achieve a fall harvest before the first frost date of the season.

Starting a vegetable garden in September is possible with cold cloches, row covers, and fast-growing vegetable varieties for fall and winter harvests. Through careful planning around the planting dates of cool-season crops, gardens can thrive during cooler months of the year before hard frosts arrive to deter plant growth.

What Vegetables to Plant in September

Cool autumn weather is perfect for starting a fall garden for essential crops like root vegetables and leafy greens. These vegetables, some flowers, and herbs grow in fall as they would in spring.

Planning for Fall Planting

To determine when and what to plant, it’s essential to determine the estimated frost dates for your USDA hardiness zone. Knowing when to sow seeds in the garden depends on how long it takes for your fall vegetables to reach maturity and harvest.

While many fall crops handle light frosts, growing vegetables in cold climates requires some planning. Not all cold season vegetables do well when temperatures drop too low. Some crops, like carrots, tolerate frosts but should be dug out of the garden before the ground freezes.

Growing Tomatoes

Although tomatoes may not seem like fall crops, they do well when grown in cool weather. Tomato plants grown during summer yield poor results because tomatoes do not thrive in warm weather. Tomatoes germinate when soil temperature ranges between 75 and 90°F and grow best in temperatures between 55 and 75°F.

Sub-Arctic, Glacier, and Manitoba are determinate varieties of tomatoes that mature in less than 60 days. These tomatoes ripen all their fruit simultaneously, perfect for a final tomato harvest before the temperature drops too much.

To get the best harvest, pinch the top of the tomato plant and remove at least six inches of foliage from each stem as your plants grow. Removing vegetation from your plants triggers the plant to focus its energy on ripening the fruit already on the plant.

Planting Alliums in September

Crops in the onion family are excellent veggie choices to plant in September. Although we often plant onions in early spring, onions are perfect vegetables to grow in September or seeds to plant in October due to the warm soil created by the summer sun. It’s a good time to plant onions in zone 6 or even zone 7.

Planting onion crops in warm soil allows onions to germinate and grow faster than sets produced next spring. After planting onions, the bulbs sprout and develop in the soil before winter starts. As the ground freezes, onions in the ground become dormant.

The following spring, the onion plants start growing again as temperatures rise and the soil warms. This growing process through dormancy results in larger onions with solid flavor. Use this same growing method to grow garlic, leeks, shallots, and green onions.

How to Grow Winter Cabbage

Winter cabbage differs from regular cabbage because they are late-season varieties that are tolerant of cold weather and are best when grown later in the season. The time to plant cabbage seedlings is in September or October, depending on your hardiness zone.

To sow cabbage seeds, rake the garden soil and amend with compost before planting seeds half an inch below the surface with at least a foot of space between each seed. Winter cabbage requires less water than other varieties, is cold-resistant, and reaches maturity in around 100 days.

Root Vegetables to Grow in September

Root vegetables grow the edible parts of their plants underground. Common root vegetables include beets, turnips, radishes, and rutabagas. Root crops tend to grow quickly; after planting them in warm soil, they develop strong roots before the weather gets cold.

Many root crops handle light frosts before the ground freezes, and you must harvest them. Kohlrabi is a fast-growing crop that reaches maturity in about 60 days. Plant seeds at the beginning of September to harvest just before winter begins.

How to Grow Herbs in September

The start of fall is the best time to plant herbs like cilantro, parsley, and chervil. These herbs are best grown in cool weather to avoid wilting foliage in the summer sun.

After planting parsley in fall, the herb finishes blooming in spring the following year. Cilantro seeds that start sprouting in fall become dormant during the winter months before it finishes growing in spring.

Although chervil does not handle extreme frosts well, it bolts in warm weather. This growing pattern makes fall the best time to grow chervil to ensure you harvest the best yield.

Sage is a popular herb that grows well after planting seeds in fall. For the best growth, planting herbs in fall should be timed for two weeks before the first frost. Sage is a perennial plant; however, in the warmer places in the USA, sage is an annual plant as it does not do well in hot summer weather.

Salad Greens to Plant in Fall

Lettuce, spinach, and arugula are delicious salad greens to plant in autumn. These plants have short growing times, so ensure you harvest your crops before the ground freezes. When you plant lettuce seedlings, it’s a good idea to mulch around them to protect the roots.

Romaine lettuce and other greens bolt easily in hot temperatures and resist cold weather and light frosts. If you’re growing salad greens in the northern United States where temperatures drop quickly, use row covers to protect your plants from harsh frosts while providing the plants with the necessary sunlight.

Sow Beans Starting in September

Some of the best vegetables to grow in September include crops that overwinter until spring weather arrives. Start sowing seeds for broad beans in September and continue stagger planting through November. When searching for what vegetables to plant in September, beans are a perfect addition to your garden for their ability to fix nitrogen levels in the soil.

As you grow beans during winter, insect pests are less likely to feed on your plants. After overwintering in the garden, your beans will continue to grow in spring to become one of the first crops to bear fruit in the new year.

Cole Crops

Cole crops are practically synonymous with cold weather and do best when grown in temperatures under 70°F. Crops that fall under the cole category are cold hardy; some taste better after experiencing light frost. When crops survive frost conditions, the water inside the plant freezes, causing the plant to become sweeter.

Plant cole crops in sunny garden spots in well-draining soil. Many cole crops are heavy feeders, so using compost in the garden ensures you get the best yield. They are great veggies to plant in November if you live in hardiness zone 8.

Flowers to Grow in September

Autumn’s start brings rich colors as leaves change and fall. These bright colors can exist in your garden by planting flowers. Flowers to plant in September include fragrant herbs, colorful plants, and edible flowers.

Chrysanthemums thrive when planted at the end of summer or the beginning of fall. Seeds germinate slowly in cold temperatures, so begin planting at least six weeks before the first frost date in your area.

Peonies are a popular flower to establish in the garden in September to get blooms in spring. Asters are perfect flowers to plant as their roots become established by frosts in the winter months.

Greens to Grow in Fall

Swiss chard is a nutritious plant that grows quickly in cool temperatures. Although Swiss chard does grow in warm weather, its growth slows due to the heat. For a fall harvest, plant chard seeds 40 days before the first frost date in your area.

Batavian endive is a broad-leaf crop that grows lettuce-like leaves in tight heads. Curly endive is a warm-season crop; however, the broad-leafed endive does well when grown as an early winter crop.

Mustard greens are versatile as a spring or fall plant. Plant mustard green seeds six to eight weeks before the first frost of the growing season. Mustard greens require consistent irrigation and germinate in a little over a week.

Collard greens are nutritious dark greens that mature in about 60 days. To get collards in the ground in time, plant them in September if you live in warmer growing zones. Like many leafy vegetables, collards become sweeter after being hit by light frosts.

Plant Peas in September

Peas should be on your list when deciding what can be planted in September. Planting peas during the year’s second half guarantees you’ll have fresh pods when spring comes the following year.

The best peas to plant are seedless varieties because they are less likely to rot than other types. Dwarf varieties are less likely to suffer wind damage during the spring season. When planting peas, establish support for your future pea plants by using wooden stakes or a tomato cage to help pea plants grow vertically.

Tips for Growing Vegetables in September

After months of warm summer weather, the soil in your garden is ideal for planting new seeds. If you live in a cool part of the country where summers aren’t hot, there are a few tricks to implement in your garden to improve the soil temperature.

If you layered mulch in your garden during previous growing seasons, rake away the mulch to allow sunlight more direct access to the soil. Another way to draw heat to your garden is by laying dark plastic sheets across your garden rows. Sunlight warms the plastic during the day, warming the soil beneath.

Late-Season Pests

Planting fast-maturing varieties may feel like you’re racing to harvest before winter hits; however, the threat of frost isn’t the only concern for gardeners. Many pests linger in the late season to feed on crops before they reach maturity.

Aphids threaten most gardens as these sap-sucking insects feed on plant foliage and leave honeydew behind. This honeydew develops into black sooty mold if left untreated.

Cabbage loopers enjoy feeding on the leaves of Brassica plants, including bok choy, cabbage, and kale. Avoiding these crops in your garden isn’t enough to keep loopers away as they also target tomatoes, some summer squash, and cucumber beetles.

Use a natural insecticide like neem oil to repel insects and protect your plants from these pests as well as many others can damage your yields. Neem oil is cold-pressed from fruits of the neem tree and works by disturbing the nervous system of bugs, affecting their ability to feed and mate.

Mix water with soap in a tank sprayer to reduce the surface tension of your water, allowing you to add the oil. Spray all leaf surfaces with this mixture to target pests and deter further insect activity.

Protecting Fall Crops from Frost

In the northernmost states of the United States, the first frost date may come as early as mid-September. Due to frosts threatening some cool-season crops, create cloches to protect your plant’s leaves.

A cloche is any coverage for plants in the garden. Cloches are available online, but they are quick and easy to make by cutting a water jug or milk container. Using a knife, slice the bottom off your container and place the top half of the container over your plant. The jug’s opening allows you to water your plant while it remains covered from the elements.

Picking what seeds to plant in September depends on your growing zone and gardening needs for the winter season. Many delicious crops grow fast enough to plant and harvest before winter arrives. Other cool-season crops are better after spending a winter in the ground where frosts improve their taste and yields in spring.

If our suggestions on vegetables to plant in September helped you decide how to expand your garden, please share our tips on what vegetables to plant in September with fellow gardeners on Facebook and Pinterest.