Growing Vegetables Indoors in Winter
Let the fall migration of food indoors begin!
As the weather begins to shift into fall, harvesting food from the garden can feel like a full time job. And yet no matter how much you grow in the summer, knowing that your access to fresh food is waning can be a serious downer for many gardeners.
But just because the colder weather is on its way, doesn’t mean gardening for the year has to stop entirely. At the first shift of summer heat to cooler fall rains (which is early September where I live in Canada), there is an opportunity to migrate some vegetables indoors for the winter months.
Growing vegetables indoors in winter is not as complicated as it might first seem. Using a combination of garden transplants and fresh new plantings, it is possible to enjoy a little garden magic even when the winter winds are blowing.
Let’s explore how indoor vegetable gardening can add a little zip to your winter food options, and brighten up your life as well.
Moving vegetables from outdoors to indoors
One of the easiest ways to enjoy growing vegetables indoors in winter is simply to migrate some of your existing garden from outside to inside. Many herbs and small vegetables are pretty easy to dig up and transplant. Think of it as reverse engineering of spring transplanting out, where instead you bring some vegetables back inside.
Steps to transplant vegetables back indoors:
1) Choose a healthy plant, free of disease or insects.
Sometimes this is easier said than done. You can usually wash a small amount of insects off using a light garden hose spray, or even some mild insecticidal soap, but you can’t wash disease off.
Carefully dig around the plant in a way that lets you lift the entire plant up with as little disturbance to the rootball as possible.
If you damage or break a lot of roots, you will need to cut the plant back by removing some of the top growth to avoid a big transplant shock.
2) Select a suitable sized pot for the plant you are moving.
It is really important to consider the Goldilocks Principle in choosing the right sized pot: It can’t be too large or too small. You need one that is just right.
What does just right look like? The pot needs to be deep enough to let you easily settle the rootball into the soil at the same level it was growing at before. The pot also needs to be wide enough that there is some room for lateral root expansion, but not be so big that the rootball you dug up is lost in the middle of a huge space. Ultimately the plant needs some room to expand it roots, but really you want it to fill the pot up quickly. Remember that you are eating this plant, not keeping it for a lifetime.
3) Use amended potting soil in the pot.
Garden soil usually becomes too compact in a pot with repeated top-down watering. Use a quality potting soil that will support good drainage.
Amend the potting soil with compost or worm castings to provide an added nutrient boost.
And/Or use a simple organic fertilizer that you can add to water every few weeks. I use Gaia Green Organics All Purpose 4-4-4 which is a nice mild and balanced fertilizer. Remember that most vegetables moved indoors will not require much fertilizer in cooler and darker winter growing conditions.
4) Provide extra light
Even if you have a bright sunny south window, you will need to provide some supplemental light to help get your vegetables to perform indoors in the winter. A light table, or the addition of LED grow lights to your houseplant space can make indoor vegetable growing a breeze.
Most vegetables thrive best with a total of 10-12 hours of good quality light. If the plants are using a window that means you probably only have to supplement a few hours in the evening to achieve the goal. If the plants are on a light table, you need the lights on for the entire time. I use timers to automatically turn the grow lights on and off at regular intervals.
What vegetables can be transplanted for indoor growing?
The easiest vegetables to transplant from your outdoor garden to your indoor garden include:
Cherry tomatoes
Hot and/or sweet peppers
Herbs like parsley, oregano, cilantro and mint
Alliums like chives, scallions and garlic
Tomatoes
Small and compact patio tomato varieties make the best choices for moving indoors. That makes cherry tomatoes a no-brainer choice for an indoor migration.
If all of your cherry tomato plants are too large to extract from the garden, don’t despair. You can easily jump start tomatoes into a pot by using cuttings.
Just select a nice stem that is 6-12 inches long. Gently twist or pull that stem away from the parent plant. Remove the lower leaves while leaving all the top leaves and flower nodes in place. Place the stem into a glass of water, making sure the water covers the spots where you removed the leaves. Then wait. In one to two weeks you will see roots forming from the part of the stem that is in the water.
Once there is a nice set of roots formed, you can transplant your tomato into a pot. Just remember to keep the pot moist for the first few weeks to allow the roots to establish in the soil. A plastic bag placed loosely over the pot can help if your home is too dry.
Peppers
I love to bring some hot pepper plants indoors for use in the winter. I usually grow some of my hot peppers in pots precisely so I can just move them inside as the warm weather wanes.
Mature pepper plants can do nicely on a bright windowsill all winter long without extra light and can hold their peppers in place for months (even right through to the following spring). Older peppers will dry right on the plant to perfection. To get new peppers you might have to supplement light and fertilizer. Usually for me there is enough existing on the plant, all I need is for the pepper to survive.
The coolest part about hot peppers is that you can take that same plant right back outside in the spring (using careful transplanting techniques) and it will keep right on producing food.
I personally don’t bother doing this with sweet peppers. Instead I dry my sweet pepper harvest in a dehydrator and use the sweet pepper flakes all winter long.
Herbs and Alliums
Herbs and alliums pot up nicely and provide a delightful fresh boost to your winter meals.
They also have the added benefit of providing some aromatherapy in winter. Just a whiff of parsley or oregano can transport you back to sunny garden days. Any time you gently brush their leaves or stems, they will release some of their delightful smells, giving you an emotional boost that can last for hours.
What vegetables can be seeded and grown in containers indoors in winter?
Other vegetables are simply much easier to re-start from seed rather than attempting to transplant them from your garden. There is a much longer list of candidates here.
Indoor winter vegetables you can start from seed include:
Lettuce
Leafy greens like mustards, arugula, and spinach
Kale and other brassicas
Carrots
Beets
Herbs like basil and dill
Microgreens
Direct from seed
The trick with these vegetables is to choose fast growing varieties (with the smallest number of days to harvest) and then choose both the container size and light regimes that will support fast and productive growth.
You can start them in small seed starter packs like you would for in the springtime and then transplant them into pots later, or simply direct seed into whatever container you plan to work with for the winter. Either way, having a few familiar garden veggies around can make winter seem a little less dreary.
For most of these plants, using a light table is the most efficient way to get good leafy growth. The lighting is particularly important because some leafy greens like spinach can accumulate too much nitrogen in their leaves in low light conditions, which impacts their nutritional value.
Microgreens
The best bang for your buck for serious winter vegetable production comes from microgreens. These power-packed, nutrient dense plant starts can be ready in as little as 7-10 days for some greens and more like 20-30 for others. Microgreens give you the widest selection of taste, texture and color for winter meals. You can grow any of the staples listed above as microgreens, or venture off into plants like pea shoots, sunflowers, grains, and any number of seed mixes for sandwiches, salads and winter soups.
My favorite microgreen seed mix is a Brassica mix. It gives me the right combination of bright flavors and spicy goodness. I love it in everything from a breakfast bagel, to salad, to a pasta topping.
Tips for growing vegetables indoors in winter
There are a few do’s and don’ts when it comes to growing vegetables indoors while the weather outside is cold and the days are short.
DO:
Provide supplemental light.
Plants prefer long day lengths and bright light in order to grow successfully and not become weak and leggy. Short winter days mean that supplemental light is a necessity.
Water less frequently.
Unless you keep your house like a sauna in the winter, your indoor temperatures will not match summer heat. That means your indoor vegetables will not need the same kind of water frequency as when they grow outside.
Monitor for pests.
Sometimes pesky critters hitch a ride inside on your plants, or even on your clothing. The trick with vegetables indoors is to act quickly to stop pests like aphids, whiteflies, fungus gnats and mites from taking over. That means checking your plants regularly for insects.
Don’t:
Expect outdoor garden volumes from your indoor vegetables unless you have invested in a specific grow/production system.
I have both a 3-tier light table system and an Urban Cultivator system for microgreens which I truly LOVE. In fact the UC is so great I save the light table mostly for transplanted garden vegetables that are in pots or for spring starts. There are other hydroponic and vertical systems that can provide larger volumes. Otherwise, it is important to keep your volume expectations in check.
Over-fertilize.
This one can be tricky because you want your vegetables to grow strongly, but over-fertilization can damage the plant and simply waste money if you are providing more than the plant can use.
The best trick here is to work from a “less is more” philosophy. Start very small with fertilization and only increase the level if you are not seeing the desired results after a week or two.
Overwater.
Too much water can spell disaster for indoor vegetables. Make sure your containers are well drained and that the pots do not stand in excess water. This will help minimize the occurrence of root rot, which can be a challenge for winter indoor growing.
If you plant needs extra humidity - because your house air is dry in winter - put pebbles under the pot so that the water drains away, but can stand in the pot tray and create extra humidity for the plant.
Savor the process and the produce
Growing vegetables indoors in winter is one way to scratch the itch of gardening even when cabin fever has you longing for a tropical vacation. Check out “Green on the Inside” for more on the amazing benefits of houseplants, which can include your winter vegetables too.
Just the sight of happily growing little vegetables on a light table or in an Urban Cultivator can boost your serotonin levels and improve your mood.
And the taste of fresh home-grown veggies in winter? Magical!
