How to Grow Vegetables Indoors

Success Starts with the Right Grow Lights

By Leslie F. Halleck, Certified Professional Horticulturist
Low Bamboo LED Grow Light GardenFruiting alpine strawberries and high-light succulents growing together in the Low Bamboo LED Grow Light Garden. At this close range, the high-output LED grow lamps create full sun conditions for flowers and fruit. (Photos by Leslie F. Halleck unless otherwise noted.)

Want to grow edibles indoors? Don't let the weather, or limited outdoor garden space, keep you from harvesting fresh herbs and veggies year-round. With the right amount of light, you can grow your own herbs, leafy greens, and small fruits indoors — even in small spaces.

The key to successfully growing any type of plant indoors is understanding how much light it needs to thrive. Different areas in your home will offer up varied levels of natural light. The average windowsill can support low- to medium-light loving plants. If you want to germinate seedlings or grow high-light edibles, such as basil and cherry tomatoes, you'll need to boost your light levels with grow lamps. This is especially true in winter months, when natural light levels are low and day lengths are short.

With the right amount of light, you can grow some types of edibles indoors.
herbs growing on a windowsill Some herbs grow well in a sunny windowsill, but light-loving types will grow best with supplemental light, especially in winter. These herbs are growing in our Galvanized Herb Planters with Rectangular Tray. (GSC photo.)

Stacked Bamboo Light Garden units with plantsThe modular Bamboo Home LED Grow Light Garden with high-output LED grow lamps can help you grow edibles in low-light areas of your home, as well as add supplemental lighting to plants in brighter rooms or next to windows.

Get To Know Your Natural Light

The natural ambient light in your indoor space may be adequate to support low- to medium-light plants, and it can supplement the light provided by grow lamps. This natural ambient light will vary depending on window size and exposure, as well as many other special factors. In general:

  • Large southern-facing windows may provide you with some direct light — especially in winter when the sun is low in the sky — as well as the brightest indirect light for the most hours of the day (in the northern hemisphere). This is an ideal location for plants that need bright indirect light.
  • Northern-facing windows will offer lower indirect light levels, but for a similar duration as your south-facing windows. This is an ideal location for low-light houseplants, but won't support most vegetables and herb plants.
  • East-facing windows will give you a shorter duration of direct bright morning sun, with shady afternoon conditions. This is a good location for some cool-loving leafy herbs, as well as blooming plants that need protection from afternoon sun.
  • West-facing windows are shady in the morning with bright direct sun in the afternoon. Plants in this location must tolerate some direct afternoon sun and a little extra heat.

The more windows you have, the brighter your space will be. However, obstructions such as nearby trees or buildings — and the time of year — can significantly reduce the amount of light to any of these locations inside your home. The farther you move towards the center of your home, the less light is available to your plants. It's common to need supplemental light from grow lamps, even when your plants are growing right next to a window. This is especially true when you're growing edibles and seedlings.

How Much Light Do Vegetables, Herbs, and Fruits Need?

Understanding basic light levels and how different plants respond to light is your first step to indoor gardening success. People and plants "see" and use light differently. What looks like a bright lamp to you might not be very efficient for plant growth. Light provided to your plants from grow lights needs to be within the right spectrum for good photosynthesis. Lamps must also provide enough volume of light for the type of plant you're growing. Skip the shop lights. Quality, efficient grow lamps that generate more light and less heat are your best bet. New innovations in LED grow lamp technology have made them good choices for growing seedlings, leafy greens and herbs, and small fruits indoors.

Edibles will require more light than your average houseplant. If your indoor light levels are low to moderate, and your light source is farther away from your plants, stick to leafy greens and shade-tolerant herbs. Sun-loving foliage herbs, such as basil and thyme, will need medium to high light levels indoors with a closer light source. Fruiting plants, such as tomatoes, peppers, and citrus, will need the highest levels of light. Germinating seedlings also fall into the high-light category.

Grow Lighting Tip: You can increase your light levels, to simulate full sun conditions, by moving your plants closer to the grow lamp. You can decrease your light levels, to simulate part-sun to shade conditions, by moving your plants farther away from your grow lamps.

Skip the shop lights. Quality, efficient grow lamps that generate more light and less heat are your best bet.

Growing Leafy Greens and Herbs

If you're just getting started, try growing low- to moderate-light tropicals and edibles. Leafy greens, such as many varieties of lettuce, mache (corn salad), watercress, sorrel, spinach, and kale grow in moderate light levels. If you think about how these plants grow in the outdoor garden, they can be maintained successfully in conditions that are partly shady. This also applies to cool-season herbs in the carrot family, such as parsley, cilantro, and fennel — as well as mints.

Lettuce growing in Bamboo Light Garden Some edibles, such as leafy greens, can grow in bright windowsills indoors, but in areas with less natural light, you'll need grow lamps for a good harvest. These lettuce plants are growing under the high-output LED lamps in the Low Bamboo LED Grow Light Garden.

Most leafy greens and cool-season herbs have a compact to medium-sized growth habit that is perfect for small spaces such as your kitchen or living room corner. Your light source can be a little farther away from these leafy crops, as they don't require intense light levels to thrive. Use a light timer to keep your grow lamps on for approximately 12 hours a day. If your light garden is situated next to a bright window, you may be able to leave the lights on for fewer hours per day.

Fertilizer Tip: Leafy greens and herbs aren't heavy feeders, but since you'll be harvesting from them regularly, be sure to feed them monthly with a natural liquid fertilizer that contains humus or seaweed, such as Plant Health Care for Seedlings & Houseplants.

Germinating Seeds & Growing Microgreens

When you're ready to get new seedlings started, or grow fresh microgreens, you'll need to step up your light levels. Seedlings are light-hungry: they require long durations of bright light to sprout successfully and vigorously. Too often, beginners attempt germinating seedlings without enough light, resulting in weak, stretched seedlings that eventually topple over and die.

Use a light timer to leave your grow lamps on for an average of 16 hours per day for young seedlings. If your light garden is next to a bright window, you can run your lamps for 14 hours. If your space doesn't have much natural light, you can run your lamps for up to 18 hours. Watch your seedlings to see how they perform.

Seedlings in Bamboo Grow LightsIn most grow light setups, the light source also needs to be very close to the tiny seedlings to provide enough light: as close as 3 to 6 inches. The high-output LEDs in the Bamboo LED Grow Light Gardens provide adequate light for seedlings to thrive up to 8" from the bulbs. (GSC photo.)

One major benefit of using LED grow lamps to start seedlings is that these lamps do not generate much heat. That means you can keep your young plants closer to the lamps to give them high light levels, without burning them.

Once your seedlings have new true leaves and are ready to be transplanted into larger containers, the transplants can be moved a little farther away from your light source — or moved from the 12" (Low) Bamboo LED Grow Light Garden unit to the 30" Medium Bamboo LED Grow Light Garden.

Fertilizer Tip: Seedlings can burn from over-fertilization. Use a natural liquid fertilizer, such as PHC Plant Health Care for Seedlings & Houseplants, at 1/4 the recommended strength to feed your seedlings weekly.

Alpine strawberries in Bamboo Light GardenAlpine strawberries flowering and fruiting in a Low Bamboo LED Grow Light Garden.

Cherry tomatoesThese cherry tomatoes were grown in a Bamboo LED Grow Light Garden in the Gardener's Supply Testing Lab. Small-fruited tomatoes like these are a better choice for growing indoors than large-fruited varieties. (GSC photo.)

Grow Fruits, Roots, and Sun-loving Herbs

When your heart is set on growing sun-loving fruits and herbs indoors, quality grow lamps are a must. Producing flowers, fruits, and large roots takes a lot of energy, so plants need intense light levels for longer periods. Crops such as tomatoes, peppers, beets, strawberries, and basil thrive and produce outdoors in full sun conditions, where they typically receive direct sun for 6 to 8 hours per day. You'll need to replicate those conditions with your grow lamps indoors.

For small space indoor growing, choose compact or dwarf fruits such as mini cherry tomatoes, compact peppers, mini-beets, or day-neutral strawberries (alpine strawberries are a good choice). The Bamboo Light Garden easily accommodates strawberries and mini-tomatoes and peppers in the 12" fixture, and compact tomatoes, peppers, and herbs in the 30" fixture. Your light source will need to be about 6 to 12 inches above the plants to provide enough light. You can always prop up shorter plants to place them closer to the light source.

Sun-loving crops will need the high-output LED grow lamps turned on for 14 to 20 hours per day, depending on the type of plant and the ambient light in your space. If you can place your Bamboo LED Grow Light Garden next to a window you can further boost light levels. If plants are not growing vigorously or flowering enough to produce good fruit yields, leave the lamps on longer.

If you keep larger fruiting edibles in containers during the warm season, it can be a challenge to keep them healthy once you move them indoors for the winter. You can overwinter dwarf citrus plants, compact figs, and many other tropical container plants and houseplants in the Tall Bamboo LED Grow Light Garden.

Fertilizer Tip: Fruiting crops are heavier feeders, so fertilize twice monthly with a natural liquid fruit or vegetable fertilizer.

 You might have noticed that not all quality and powerful grow lamps and fixtures are attractive. Meaning, you wouldn't want to hang them in your living room! The Bamboo LED Grow Light Garden's good looks are right at home in any living space. They're available in three heights fit for seed starting and high-light plants, leafy greens and herbs, and larger container tropicals and edibles.

For more in-depth information on growing edibles and ornamentals indoors with grow lighting, check out Leslie's book Gardening Under Lights: The Complete Guide for Indoor Growers, published by Timber Press.

Last updated: 06/14/2024