How to Grow Your Own Vegetables and Herbs Indoors
Growing vegetables and herbs indoors isn’t difficult, but it does take planning and commitment. Just like those grown in an outdoor garden, vegetables grown indoors need all the right conditions to thrive and produce a good harvest.
In this article, we’ll review the different kinds of vegetables and herbs, what conditions they need to grow well, and how to create those conditions indoors. We’ll also explore some of the best vegetable and herb varieties for container growing indoors.
Learning Objectives
- What are different kinds of vegetables and herbs to grow indoors
- Starting from seed or buying young starter plants
- How to grow vegetables and herbs indoors
- Choosing vegetables and herbs to grow indoors
Table of Contents
Kinds of Vegetables and Herbs to Grow Indoors
There are several types of vegetables and herbs that can be grown indoors, including leafy greens, sprouts, microgreens, and vegetable plants that produce a fruit (e.g., tomatoes). The herbs we use for cooking are the leaves, or sometimes seeds, of plants.
Botany vs. Culinary: What’s the Difference? The term “vegetable” doesn’t mean anything in the world of botany. It’s just a word we use to describe something plant-based we eat as part of the main course of a meal, rather than for dessert.
In the world of plants, a “fruit” is the specific part of a plant that contains the seeds and develops after a flower has been pollinated (e.g., rose hips, raspberries, apples, peaches, tomatoes, and squash). While we think of fruits as things eaten for breakfast or dessert, many of the fruits we eat are commonly referred to as “vegetables,” such as tomatoes, cucumbers, peppers, and squash.
We eat lots of different parts of the edible plants we call vegetables, including the roots (e.g., carrots), stems (e.g., celery), leaves (e.g., spinach), flower buds (e.g., broccoli), and fruit (e.g., cucumbers). Sometimes we need to wait until the fruit is ripe, and sometimes we can harvest leafy greens before they’ve fully matured.
Let’s look at the different types of vegetable plants that can be grown indoors:
Sprouts
Sprouts are very young vegetable plants that have only just started to grow. The seeds have germinated and developed young pale stems and a small root, but no leaves other than the two cotyledons (the food-storage seed leaves) that provide energy before the plant can manufacture food through photosynthesis.
Microgreens
Microgreens are also young vegetable plants grown from seeds, but they’re harvested a little later than sprouts. Microgreens are harvested when the young plants have grown a few true leaves and are about 3 inches tall. Examples include kale, peas, broccoli, radishes, and carrots. The taste of microgreens varies from peppery to bright and fresh. They’re one of the most cost-saving vegetables to grow at home; for the cost of one store-bought package, you could purchase a whole packet of seeds to grow multiple fresh batches.
Leafy Greens
Leafy greens include lettuces, spinach, and kale—any plant whose leaves we harvest to eat. These tend to be some of the easiest vegetables to grow indoors because they don’t grow very big, and many of them can grow in lower light conditions than other vegetables.
Other Vegetables
Other vegetables that can be grown indoors are those that produce fruits we can eat, like tomatoes and peas, and those whose roots we find tasty, like radishes and carrots. All of these can be grown indoors if given adequate light and plenty of room.
Starting From Seed or Buying Young Plants
Vegetables and herbs grown indoors can be started from seed or from young plants purchased from your local garden center.
The choice of growing vegetables and herbs indoors from seed or young plants purchased from the local garden center often depends on what types you want to grow. Some vegetables are always grown from seed because they don’t transplant well (e.g. carrots and radishes). Others, like many herbs (e.g. rosemary or mint) can be difficult to grow from seed, so it’s best to purchase young plants. If you have a friend with a mature rosemary plant in their garden, you can also take cuttings to root and grow your own new plant.
The biggest benefit to purchasing young plants is that it saves time; you don’t need to spend a few weeks growing the seeds. Purchasing young plants means you’ll get to harvest your crop sooner. The downside to relying on purchased plants is that they’re only available at garden centers in spring or fall, and the selection is usually limited. It’s also more expensive to buy starter plants; for the price of one plant you can often get a packet of 20 or more seeds.
A benefit to starting your indoor vegetables from seed is that you can start them at any time of year; you don’t need to rely on the garden center’s schedule. You might also want to grow rare or unusual varieties that can only be found by purchasing seeds online.
Whether you start your vegetables and herbs from seed or starter plants will depend on what you want to grow (and when), how long you want to wait for a harvest, and how much you want to spend.
How to Grow Vegetables and Herbs Indoors
Growing vegetables and herbs indoors requires some planning. They need the right conditions to grow well and produce a successful harvest. It can be a challenge – but not impossible – to recreate outdoor growing conditions in an indoor setting. Some varieties are easier to grow than others, and some are simply best left for the outdoor garden.
The most important element is light, both in duration (number of hours) and intensity (how strong it is)
Sunlight shining indoors through a window is less intense than outdoors. As a result, plants need more hours of direct indoor sunlight than they would growing in an outdoor garden. Most vegetables grown indoors will need the addition of plant lights to supplement what natural light they may get through the windows, but it depends on what you choose to grow. Sprouts, for example, don’t need a lot of light, and many leafy greens need less light than other vegetables like tomatoes and peppers.
Growing Sprouts Indoors
Sprouts take up the least amount of space to grow indoors, and can be harvested much sooner than anything else. They’re grown from seed and harvested in as little as 2-3 days after the seeds germinate (start to grow). The whole young plant – roots, shoots, and seed leaf – is harvested soon after germination so they don’t need to be grown in soil.
They’re usually grown with seeds sprinkled on a moist growing medium like a paper towel, in a specially-designed shallow tray with a strainer, or in a jar. Think of the alfalfa sprouts you buy in a plastic clamshell at the grocery store. Sprouts are easy to grow because the seeds don’t need light to germinate, so they can be grown anywhere. After harvest, a new batch of seeds needs to be sown.
Growing Microgreens Indoors
The term “microgreens” simply refers to young vegetable plants grown from seed and harvested at the growth stage when only a few leaves have developed, usually within 7-14 days of sprouting. Any vegetable with edible leaves can be grown as microgreens, including peas, kale, broccoli, radishes and Swiss chard. (Note: Members of the nightshade family like tomatoes and peppers have toxic foliage, so they can’t be grown as microgreens.)
Growing microgreens indoors is easy but needs a bit more of a set-up than sprouts, since microgreens need soil and light for the plants to grow to a harvestable size. They can be grown on a sunny windowsill that gets at least 4 hours of direct sun, but they grow best under artificial lights. They are generally grown in soil so they can develop a root system to support leafy growth. The young plants are harvested by cutting them at soil level, leaving the roots behind in the soil.
Microgreens aren’t difficult to grow, but they need a few minutes of attention daily to check on moisture levels and overall health of the young plants. Microgreens are one-harvest plants; once they’re cut, new seeds need to be sown for another harvest.
Growing Vegetables and Herbs Indoors
Growing vegetables and herbs indoors requires just as much planning and almost as much of a time commitment as growing them outdoors. It can be done, but it’s not always easy.
Challenges of Growing Vegetables Indoors
Providing the ideal growing conditions for vegetables indoors can be challenging (see below), but with determination it can be done. That said, indoor harvests may not be as bountiful as an outdoor garden. In addition, there are characteristics of some plant varieties that simply make them poor options for an indoor garden.
One consideration is plant size and growth habit. Unless you have a large space like an enclosed balcony or sunroom you can dedicate to larger plants, there are some you’ll need to forego. For example, squash plants have large leaves and grow on trailing vines several feet long. Indeterminate tomatoes can grow several feet tall, producing flowers and fruit over a long growing season; not impossible to grow indoors, but they’ll need a lot of space.
Another important consideration is whether or not the vegetable needs a pollinator to produce a crop. Some, such as peas and tomatoes, are self-pollinating and don’t need another plant for pollen to set fruit. Others, like squash or cucumbers, produce male and female flowers on the same plant but need a pollinator to transfer pollen from the male to the female flowers. Plants like these that aren’t self-fertile will need to have their pollination done by hand indoors, using a paintbrush or cotton swab.
Growing Conditions for Vegetables Indoors
Vegetables and herbs need the right conditions to grow well and produce a successful harvest. It can be a challenge – but not impossible – to recreate outdoor growing conditions in an indoor setting.
Here are the growing conditions you’ll need to consider
Light Levels
Vegetables need a lot of sunlight, which is the most important consideration – and one of the biggest challenges – when growing them indoors. Once you’ve assessed your living space, you’ll know which areas get the most natural sunlight. These are the spots you want to use to grow your vegetable plants. Vegetables that produce fruit (e.g., tomatoes, cucumbers, peppers) and leafy herbs (e.g., rosemary, thyme) need at least 8 hours of direct sun to produce a decent crop in an outdoor garden.
Grown indoors, where the light is less intense, they will need about 16 hours of direct light. This will probably mean the use of plant lights to supplement any natural light. Leafy crops like lettuces can tolerate a little less light but still need at least 6 hours of direct natural sunlight indoors.
In cases when natural light isn’t an option, plant lights can be used to provide the necessary light for growing vegetables indoors; most will need at least 10-12 hours of artificial light a day. Vegetables that produce a fruit, such as tomatoes, need a particular type of plant light that produces light of the correct wavelength to stimulate flowering and fruit development.
The Right Container
Any container used to grow plants indoors needs to have proper drainage holes in the bottom so that excess water can flow out of the container. Without good drainage, water collects in the bottom of the pot and moisture builds up in the soil. Too much moisture in the soil leads to root rot and death of the plants.
You’ll also want to match the size of the pot to the mature size of the vegetables you want to grow. The bigger the variety of vegetable plant (i.e., the taller and bushier the plant is going to get), the more soil depth you’ll need to support the plant’s root growth and to anchor the weight of the top growth so the plant doesn’t fall over.
In addition, the deeper the soil, the more moisture it will hold and the less frequently you’ll need to water your plants.
You can grow smaller vegetables, like lettuce and radishes, in soil about 8 inches (20.32 centimeters) deep. Smaller greens like leaf lettuce can be grown in pots as small as 4 inches across and deep – one plant per pot if that’s all you can find – but most vegetables will need more depth. Larger plants like bush beans and tomatoes will need soil at least 12 inches (30.48 centimeters) deep.
Standard window boxes are a good choice for smaller varieties like lettuces or herbs. You can plant more than one plant in a window box, but be sure to leave enough room around each plant so they aren’t crowded and get good air circulation once the plants grow in.
Self-watering containers are an option for vegetables and are good choices for things like tomatoes and lettuce that need the soil consistently moist (i.e., it doesn’t dry out between watering). These are specially-designed pots with a built-in water reservoir that plants can draw on as needed for an extended period of time. After watering the plant thoroughly from the top after planting, the reservoir is filled with water. The plant draws water from the reservoir as needed. Rather than watering the plant regularly, you ensure the reservoir doesn’t dry out. A self-watering container will also have a water-level gauge so you can tell when the reservoir needs to be refilled.
Potting Mix
There are plenty of different soil blends available at your local garden centre, but not all of them are suitable for growing vegetables indoors. Potting mixes for general indoor gardening use will be labelled “potting mix,” “container mix” or “soilless mix.” They will be varying blends of peat moss or coconut coir, perlite (the little white bits), vermiculite (the little shiny bits), and sometimes compost, sand or small pieces of bark. For growing vegetables, look for mixes that are labelled “all-purpose” since these will be light and contain plenty of organic matter. You may even find a blend labelled specifically for growing vegetables in containers.
Some commercial potting mixes also contain slow-release fertilizer in the blend to feed plants over several weeks. After six weeks or so, once your vegetable plants are several inches tall with lots of leafy growth, the nutrients in these ready-made mixes will probably be depleted. You’ll then need to start using fertilizer on your vegetables. Be sure to check the label of the potting mix you purchase so that you don’t add fertilizer unnecessarily; too much fertilizer can damage plants. Also be sure to follow instructions on the fertilizer product you plan to use.
Fertilizer
Vegetable plants are heavy feeders – especially those that produce a fruit or root we eat – and will need fertilizer to grow well, especially in containers. All-purpose potting mixes generally don’t have a lot of nutrient value – unless a fertilizer has been added to the blend – so to grow vegetables, it will be necessary to add fertilizer to the mix before planting or use a fertilizer throughout the growing season.
What type of fertilizer you use will depend on the type of plants you’re growing.
All fertilizers have the letters N-P-K on the label, along with numbers such as 6-8-6 or 20-20-20. The letters stand for the nutrients nitrogen (N), phosphorus (P), and potassium (K). The numbers refer to the percentage of each nutrient in the mix (the higher the numbers, the stronger the fertilizer). The amounts of each nutrient in a mix aren’t always even; some mixes will have higher levels of one or two nutrients, depending on what sort of plants they’ve been designed to support. There are fertilizers available that are formulated and labelled specifically for growing vegetables.
- Nitrogen (N) supports leafy green growth
- Phosphorus (P) supports the growth of roots
- Potassium (K) supports overall health of the plant, and the production of flowers and fruit.
Leafy vegetables such as lettuce, spinach and kale will need plenty of nitrogen (N). Fruiting crops will need a fertilizer with a higher proportion of potassium (K).
Herbs grown in containers need fertilizer but less than vegetables; how much will depend on the variety of herb. Most perennial herbs are native to the Mediterranean, where they grow in arid conditions and less fertile native soils. They get their flavor from the essential oils they develop in their leaves to withstand drought. It’s these oils that give herbs the flavors we enjoy. Too much fertilizer will result in spindly growth and fewer oils in the leaves, and therefore, less flavor. Fast-growing herbs with thinner leaves such as chives and annual herbs such as basil, cilantro, and dill will need more fertilizer than the Mediterranean herb varieties.
Get to know the specific needs of each vegetable and herb you choose to grow before you add any fertilizer.
Watering
How often you need to water your vegetable plants will depend on what you’re growing, as well as the growing conditions. Some vegetables, like tomatoes and lettuce, need their soil to stay consistently moist. Others, such as many herbs, prefer to have their soil dry out a bit between watering. If a room is kept on the cooler side, soil will dry out more slowly, and plants need watering less frequently than in warmer conditions.
Check the soil moisture of your plants regularly – at least once or twice a week – until you become familiar with how much water they’re consuming. You may check your plants regularly, but they may not need watering every time you check on them.
Humidity
The air indoors can be very drying for plants, especially in homes with indoor heating in winter. Some plants, like many herbs, don’t mind these conditions, but others like sprouts and leafy greens prefer a little more humidity. To help these vegetables stay better hydrated, use a spray bottle on the mist setting to moisten the air around your plants every day or two.
You can also stand your plant pots on a large tray of pebbles filled with water (be sure the pot sits OVER and not IN the water). The water will evaporate and keep the air a little more humid immediately around the plants.
You can also use a small cool-air humidifier for groups of plants in a larger space.
Temperature
Most vegetables grow best with indoor air temperatures 60-75 degrees F (15-24 degrees C). This is within the range most of us keep our homes. Plants also like consistent temperatures without sudden extremes like drafts from a window or outside doors. It’s also important to keep vegetable plants away from sources of indoor heat like wood stoves or heat vents. The same applies for air conditioners; keep plants out of the direct airflow from AC units.
Air circulation
Plants grown indoors need good air circulation around them to help prevent fungal diseases. Place individual containers far enough apart so the plants’ foliage doesn’t touch. Large groupings of plants benefit from a small circulating fan set up to move air gently through the space. A fan will also help pollinate those vegetables that need it.
Hydroponic Growing
Most vegetables grown indoors are in containers of potting mix. However, it’s also possible to grow things like microgreens and leafy greens entirely in water. This is a method known as “hydroponics.” Hydroponic systems have a reservoir to hold a water-fertilizer blend plus grow lights held over the small plants. Seeds are sown on a special growing mat and then root down into the water. Hydroponic systems can be small tabletop set-ups or larger towers.
Choosing Vegetables To Grow Indoors
Many vegetable plants grow large and bushy, making them impractical to grow in containers in confined indoor spaces. Fortunately, many smaller or dwarf varieties are well-suited for growing in containers and won’t overcrowd indoor living spaces.
The following is a list of some of the easy-to-grow vegetables and herbs well-suited for growing indoors.
Arugula
Arugula is a good choice for growing indoors. It can tolerate less sun than other crops and matures quickly so you don’t have to wait too long for a harvest. It can take as little as a month from seed to harvesting young leaves. The leaves add a nice peppery flavor to salads or stir-fries. Mature leaves have a stronger flavor than leaves cut when young.
Lettuces
Lettuces grow well indoors, since they only need about 6-8 hours of direct sun through a window, or 12-14 hours under a grow light. They also prefer cooler temperatures to grow well. There are lots of lettuce varieties to choose from. Some form heads for a single harvest and others grow smaller, looser plants (“leaf lettuce”) that can be harvested a few leaves at a time over a long growing period. Choose leaf lettuce varieties to grow indoors so you can harvest a few leaves as you need them, for a longer harvest period.
Kale
Kale can be started from seed and grown as a microgreen, with the young tender leaves harvested for use in salads. It can also be left to grow to a larger size for use in soups or gently steamed as a side dish. Choose smaller varieties for growing in containers, such as dwarf curled Scotch or Siberian dwarf. Kale grows best with at least 4 hours of direct sun daily; in a south-facing window in summer. To grow it in winter, use plant lights for 10-12 hours a day.
Spinach
Spinach is another leafy green that tolerates lower light levels and can be harvested when the leaves are young or left to mature. Grown from seed, it can be ready to harvest in as little as 25 days. Spinach prefers several hours of indirect sunlight, such as an east or west-facing windowsill. To grow it in winter, use plant lights for 10-12 hours a day.
Peas
Peas are another vegetable that can be grown as a microgreen, harvesting the plants once they’re a few inches tall. They can also be left to grow on a flower to produce pea pods. They are a vining plant and will need a trellis to grow on. They’ll also need a good 10 hours of direct sun or light from a plant light to flower. They can be grown indoors because they are self-pollinating; they don’t need a pollinator like bees to develop the edible pods.
Potatoes
Potatoes need a little more attention – and patience – to grow indoors than other vegetables. Plants are started the same way as in an outdoor garden, with potato “chits” (pieces of potato that have been prepared before planting, each having developed sprouting bits called “eyes”) planted in about 4 inches of soil in the bottom of a container at least 2.5 gallons in size. More soil is added to bury the stem as it grows. (The potatoes we harvest are tubers that grow off the buried stem.) Choose smaller potato varieties such as fingerlings for a better harvest. Find a window that gets 8-10 hours of direct sun in a day in summer, or use grow lights for 12 hours a day.
Carrots
Carrots can be grown indoors, but they require patience. The seeds can take up to two weeks to germinate, and then it takes another 57-75 days for the carrots to develop, depending on the variety. Use a container that’s 8-12 inches deep and choose smaller varieties, such as Little Fingers, that will grow to a decent harvestable size in limited space. Carrots need at least 6 hours of direct sun each day; 8 hours under a grow light. Note: Cutting off the top of a carrot – with greens still attached – and placing it in water will not grow more carrots. Yes, the carrot piece will grow roots, but these won’t develop into more carrots, even if planted into soil. However, the greens will continue to grow, and these are edible! They make a tasty addition to soups and salads.
Radishes
Radishes are one of the easiest and fastest-growing vegetables for indoor gardening. They can be grown as microgreens or left to mature and grow an edible root for harvest. They’ll need 6 or more hours of direct sunlight – a south-facing summer window would work well – or the use of grow lights for about 10 hours a day. They’re a “cool season” crop and prefer temperatures under 70 F (21 F).
Tomatoes
Tomatoes come in two types: determinate and indeterminate. Choose determinate varieties to grow indoors, since most of these grow to heights under 4 feet. Many of them won’t need cages or other structures to support their greenery. Indeterminate varieties keep growing like vines indefinitely, producing more flowers and fruit for an extended harvest period. They’ll take up a lot of room and need a trellis or other support for their greenery.
Tomatoes are self-fertile (don’t need another plant for pollination) but they will need help to pollinate themselves. You can transfer pollen from one flower to the next using a cotton swab or small paintbrush. Alternatively, you can set up a small oscillating fan in front of your tomato plant(s) to create a light breeze to shake the flowers and spread the pollen.
To save space, look for tomato varieties that are dwarf plants or described as well-suited for containers like “Patio” or “Tiny Tim.” These varieties will be nice compact plants that don’t need support like larger varieties. Also consider a variety called ‘Tumbler’ that can be grown in a hanging basket.
Herbs
Most herbs need full sun in an outdoor garden. Grown indoors, they’ll need 12 – 16 hours of light each day, usually from plant lights. Grown from seed, they can be ready to harvest in as few as 45 days, depending on the variety, although most will take much longer to develop into a mature plant with enough foliage to harvest without killing the plant.
Easy-grow options include chives, mint, oregano, and thyme. Parsley, dill and basil can also be grown indoors, but these plants are short-lived and will need replacing after a year (dill and basil) or two (parsley). Other varieties, such as rosemary and mint, are harder to grow from seed and are best grown from young plants purchased at the local garden center.
For a large, beautiful edible houseplant, try growing bay laurel (Laurus nobilis). Bay leaves are very aromatic and can be added to soups and stews. It’s an attractive, fast-growing plant and can reach several feet tall in two or three years. Put a bay laurel in front of a south-facing window to give it as much sun as possible.
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