Indoor gardening is gaining popularity as more and more people flock to the cities. So, how do you grow vegetables inside, and which ones should you be planting?
Herbs and true vegetables, like leafy greens, can flourish indoors with supplemental lighting, air circulation, and adequate nutrition. Flowering vegetables, like tomatoes, peppers, and cucumbers, require more care and may even need a specialized growing system depending on how much you want to grow.
As always, the key to knowing what to grow and how much is planning. Look through the plant list and write down which vegetables you eat on a regular basis, then start planning your indoor garden space.
Purchase an indoor vegetable garden seed starter kit (link to Amazon).
The Basics of Indoor Vegetable Gardens
Before you decide which vegetables to grow, you need to calculate the space you have to grow them. This could be anything from a small windowsill to an entire extra bedroom or basement.
Don’t forget to calculate cubic feet of growing space. A small, 2’x3’ space can hold a 6’ tall vertical planter with lots of lettuce and herbs.
As you take your measurements, take note of the following:
- Light intensity. Even the brightest windowsills are usually too dark to grow most vegetables without supplemental lighting. However, a room with lots of natural light may only need a few LED lamps, while a basement room will need suspended LED panels.
- Light duration. Bright, natural light is great, but if you only get a few hours in the morning, you should treat that part of your home as though it gets no light.
- Air circulation. Indoor plants are more susceptible to pests and diseases that thrive in environments with little or no airflow. If your growing area doesn’t have good circulation, consider adding a small fan.
- Durability. Growing media and water will inevitably spill onto the floor and surrounding items in your growing area. Make sure you remove any valuables that may be ruined with water or soil.
Some seed packets or plant labels will say certain vegetables, like spinach or lettuce, tolerate light shade. However, even though you may have a bright indoor living space, your house lights cannot provide the right kind of light plants need to grow.
Without direct LED lighting, plants in your home are essentially living in the shade. Don’t mistake a bright room for direct sunlight.
Basic Indoor Vegetable Garden Systems
Indoor systems have become a bit of an obsession in the horticulture world. Between aquaponics, hydroponics, aeroponics, vermiponics, and all of the variations on traditional container gardening, there are too many options to cover in this article. (Read more on water-based growing systems here)
Beginner Indoor Vegetable Garden System
The cheapest, simplest indoor vegetable gardening system is growing in pots or containers in a windowsill. The type of plants you grow will depend on how much light your windowsill receives, but this setup can work well for leafy greens, herb, and peas.
Intermedia Indoor Vegetable Garden System
When your indoor gardening outgrows a windowsill, it’s time to start planting vertically. Shelving systems, container systems, and indoor raised beds are all good options for expanding your indoor garden space.
These systems also allow for a deeper root system, more grow light options, and taller top growth. So, as you expand your systems, you also have the option to grow different plants. This system works well for almost all plants except fruits.
Advanced Indoor Vegetable Garden System
Advanced systems are anything ending in ponics, which means grown in water:
- Hydroponics. Plants grown in water.
- Aquaponics. Plants grown in water that is also home to fish.
- Aeroponics. Plants suspended in the air and misted with water.
- Vermiponics. Plants grown in water that is also home to worms.
These systems allow you to grow a large variety of plants, but they can also be expensive and time-consuming. These are best suited for hobbyists or growers who want to replace a significant amount of their diet with homegrown foods.
Vegetables That Grow Well Indoors
Any vegetable can be grown indoors with the right equipment. This list will focus on common vegetables and how easily they can be grown in the above-mentioned systems.
1. Lettuce: Any System
Most beginner indoor garden systems are geared towards growing salad greens, and the easiest salad green to grow is lettuce. Lettuce will need direct light and air circulation or else whiteflies will invade and make the leaves inedible.
The best part about growing lettuce, and most other salad greens, is that a few plants can grow a substantial amount of food. Make sure you plant cut-and-come-again varieties to ensure a steady supply of greens.
2. Kale, Chard, & Spinach: Any System
These three plants are all brassicas. While they have similar growing requirements to lettuce, they are a bit more needy. Brassicas are susceptible to nematodes that can cause root problems, and they also attract more pests than other plants.
Use lime or another pH-adjusting amendment to raise the pH of your growing media to about 7 before planting these greens. And keep them fertilized! Brassicas are extremely nutritious, but that’s because they are heavy feeders while they’re growing.
3. Fleshy Herbs: Any System
Fleshy herbs, like basil, parsley, or chives, are tied with lettuce for easiest indoor vegetables. These herbs can tolerate indirect lighting as long as they are watered properly and have adequate airflow.
Most herbs die from overwatering, so try to plant herbs in terra cotta pots and only water when the top 1” of soil is dry.
4. Woody Herbs: Containers
Woody herbs, like rosemary, lavender, and thyme can tolerate indoor growing, but they will only thrive with full, direct light. Woody herbs prefer dry growing conditions, so they do not tolerate any of the water-based systems like hydroponics.
Woody herbs are almost impossible to start from seed. However, they are easy to propagate with cuttings.
5. Peas & Beans: Any System
While these legumes can be grown in any type of system, they are picky about lighting. Even if you grow them in a bright windowsill, you should install an LED lamp or panel to encourage flowering. Any flowering/fruiting vegetable requires more energy, which means more light.
Use dwarf bush varieties for indoor growing- especially if you are growing them in a hydroponic system.
6. Tomatoes, Peppers, & Eggplant: Containers or Water-Based Systems
These fruiting vegetables are large, heavy feeders. Windowsills are too small and may get too cold at night. These plants need heat and a large root space to flower and fruit, which makes them ideal for large indoor pots or a hydroponic system.
This YouTube video host shares some great insights into growing hydroponic tomatoes indoors:
Make sure you fertilize and water consistently, and that you provide plenty of full-spectrum light. Plant determinate varieties of tomatoes and keep them pruned.
7. Cucumbers, Melons, & Squash: Containers or Water-Based Systems
These fruiting vegetables are too big and temperature-sensitive to thrive in a windowsill. They are heavy feeders and major water-hogs, which makes them ideal candidates for larger hydroponic systems.
You can grow them in containers, but you must provide some sort of support system. Try to grow dwarf varieties, if possible. These vines need lots of light and warmth to flower.
These vines will not fruit without manual pollination. These plants rely on insects for pollination between the male and female flowers. If you grow them indoors, you need to mechanically pollinate the flowers with a paintbrush in order to get fruit.
Vegetables That Cannot Be Grown Indoors
Although someone somewhere has probably built a system to successfully grow these plants indoors, it is difficult and not worth the investment unless you want to grow them on a large scale.
Carrots, Radishes, & Turnips
Root crops are difficult to grow indoors. Plus, they take up valuable growing space for a very small reward. These root crops are also susceptible to pests in an indoor setting, and they don’t perform well in containers.
Onions & Garlic
These have similar problems to the root vegetables listed above. Root crops tend to like colder growing conditions, and they can rot or mold when they’re grown in a warmer, indoor environment.
However, onions and garlic can be grown in larger, outdoor containers on a balcony or patio.
Indoor gardening’s main challenge is climate. Each indoor growing space has a unique climate, while outdoor spaces are relatively predictable and uniform in each region.
Don’t get discouraged if a certain vegetable or system doesn’t work for you. Your home has a unique environment, and it may take time to experiment with the best containers, growing media, plants, watering system, and lighting. It’s as much an art as it is a science.
Read Thriving Yard’s article on next-gen gardening systems for more information on selecting and building your own water-based indoor garden.