The freshest vegetable produce does not come from a local vendor or a supermarket. It comes from your garden.
I, being the avid gardener that I am, have been growing my vegetables for a decade now. I have compared my vegetables to commercially-grown produce several times and have always found them to be fresher and tastier!
In this blog, I will share some useful guidelines to help you get started on cultivating vegetables all year round inside a greenhouse that you can build in your backyard.
Growing Vegetables in a Greenhouse
A greenhouse is an excellent asset to a vegetable garden. Even a small, unheated greenhouse structure will allow you to extend the growing season and produce healthy crops of a wide variety of fresh vegetables.
Benefits of Growing Vegetables in a Greenhouse
1) Longer growing season: One of the main advantages of a greenhouse is that it allows for an extended growing season. Since the structure retains heat by trapping the sun’s radiation, temperatures do not vary much inside the greenhouse. Even in cold climates, you can grow the vegetables you like!
2) Minimal insect/pest danger: Predators such as moles and rodents can easily be kept out to protect the vegetable crops inside the greenhouse. Greenhouse plastic in the form of screens and traps can keep insects and pests away from the crops.
3) Weather protection: Bad weather, such as winter blizzards, dust storms and snow, can destroy your outdoor vegetables. A greenhouse acts as a layer of protection against these dangers.
4) Green advantage: Greenhouse growingis not just about providing maximum benefits to the growing plants; it’s also about living a more eco-friendly life. Adding more vegetables creates a much cleaner atmosphere, making a greenhouse an excellent tool to fight against global warming.
What Vegetables Can You Grow in a Greenhouse?
Choosing the right kinds of vegetables to grow inside a greenhouse is critical for the overall
success of greenhouse plants. Here is a list of some vegetables you can grow inside a greenhouse:
- Cucumber
- Sweet potato
- Tomato
- Pepper
- French beans
- Kale
- Broccoli/Calabrese
- Leeks
- Cabbage
- Lettuce
- Onion
- Brussel sprouts
- Sweet corn
Unfortunately, not all vegetables can be grown inside a greenhouse. Vegetables that need cold frames or full and direct sunlight will not grow well inside a greenhouse. Examples include carrot, radish and rutabaga.
When to Use a Greenhouse for Growing Vegetables
For cost-effective cultivation, you should grow greenhouse veggies as per the following timeline:
Late Winter to Early Spring:
Hardy plants, such as Brussel sprouts, leeks, cabbage, lettuce and onions should be sown between late winter and early spring, so they plant out when the warmer weather arrives.
If you have a heated propagator in your green house, you can plant peppers and tomatoes during this time as well.
Mid Spring:
Tender, fast-growing plants such as cucumbers, French beans and sweet corn must be sown in mid-spring, so they are ready for their final plantation under glass in late spring or early summer.
If you have an unheated greenhouse, mid-spring is the best time to buy grown tomatoes and peppers and introduce them to their new environment.
Late Spring to Early Summer:
This is the time to plant all your vegetables in their final position. Acclimatize your indoor-sown vegetable plants to outdoor conditions once the frost has passed.
Mid-Summer:
Utilize this time to harvest your summer crops, remove spent crops and weeds, and sow the seeds of cool-weather crops such as broccoli, calabrese and parsley.
Late Summer:
In late summer, sow lettuce and salad leaves to make use of the autumn sun.
Late summer is also the ideal time to plant sweet potatoes in a heated greenhouse so you can have the harvest ready by Christmas!
Autumn:
Remove spent summer crops and plant lettuce, calabrese, parsley, and broccoli to mature by winter.
Sow any hardy plants, broad beans and peas in autumn so you can plan them out when the weather becomes much more manageable in early spring.
Move delicate plants, such as herbs, into pots to protect them from the winter snow and blizzards.
How to Grow Vegetables Year Round in a Greenhouse: A Step-By-Step Guide
Step 1: The Planning Process
You must choose the location for your greenhouse based on your garden’s size and the type of greenhouse you want to build or buy. The ideal location for a greenhouse, as described by New Mexico State University (source), is one that has a moderate temperature, bright light and low humidity.
Unlike your backyard, your greenhouse does not have unlimited space. Therefore, you must carefully plan out the entire process before beginning. Measure beds and floor spaces. Check if you have room to space out all the vegetable crops that you plan to cultivate.
Group your vegetables based on their characteristics. If you plant vegetables that grow best in similar environmental conditions, it will be easier for you to control the lighting, humidity levels, heating and amount of watering.
Step 2: Select Containers and Soil for Sowing
Once you have planned out your greenhouse’s layout and selected the vegetables, it’s time for you to begin. Start by picking out containers that can drain excess water. They must be spacious enough for your plants to grow in.
The type of growing container you select must depend on the vegetables you chose to grow and whether you will pot them or plant them directly into the ground. Potting does not require any additional building and is a good option if you are a beginner.
Ensure that you use high-quality, fertile soil that preferably has compost mixed in. Compost holds heat in the winter, which will help you save on the cost of heating and adds fertility to the soil.
Sow the seeds in containers, following the instructions mentioned on the seed packet. Allow the seeds to germinate on a sunny windowsill or a heated area inside your greenhouse.
Step 3: Control the Greenhouse Environment
a) Lighting:
Place your plants in areas where they will receive the maximum sunlight during the day. On cloudy days and at night, you can rely on your lighting system to give your plants the extra light they require.
If you live in a region that has few sunny days during the winter, you must have an adequate lighting system in place. I suggest installing LED lights because they give high output at a low cost.
b) Humidity:
The humidity levels needed depend on the climate in which you live and the type of crops. It is best to grow plants that thrive in dry weather if you live in an arid region and humid weather if you live in a humid area.
Increase humidity levels by misting your crops. You can also install a humidifier if you think there is a need.
c) Temperature:
Keeping a good thermometer in your greenhouse is the easiest way to make sure things are as they should be. It should record outdoor indoor temperatures to help you monitor it. You can then increase heat or cool your greenhouse as needed.
Insulating your greenhouse can help you save money on providing heat electrically. One way to insulate it is to use bubble wrap along the walls of the greenhouse. You will most likely need to install a heating system depending on how cold it gets wherever you live.
Step 4: Planting the Crops
When you have created ideal conditions, you must go ahead and plant your crops as soon as they are well-rooted. In large grow bags or containers, plant them into the greenhouse borders. Ensure that all plants have sufficient support. If needed, use strings or canes to tie them.
Step 5: Maintain Your Vegetables
During summer, water daily or install an irrigation system (video). Ensure even watering to prevent root rot. Ventilate the greenhouse and provide shade gradually, so it does not reduce crop growth.
During winter, keep the structure clean. Remove snow and fit insulation structures if bubble wrap is not doing the intended work. Ensure the thermostat works to maintain minimum night-time temperatures.
Frequently-Asked Questions
- Can Vegetables Be Grown in a Greenhouse Year Round?
A. Yes. You can grow many vegetables all year round in a greenhouse as long as you provide the ideal growing conditions. However, not all vegetables can be grown indoors. For example, vegetables that require cold or direct sunlight will not grow well in a greenhouse.
- Can You Grow Tomatoes All Year Round in a Greenhouse?
A. The answer is yes! Luckily, you are not restricted to the warmer months if you have a greenhouse. You can grow delicious tomatoes all year round! However, tomatoes are picky plants, so you need to monitor their growing conditions carefully.
- Can You Grow Plants in a Greenhouse During Winter?
A. Yes! There are several plants you can grow in a greenhouse during winter. They probably won’t grow as fast as they would in the warmer months, but they will still flourish as long as you protect them from winter winds, blizzards, snow and storms.
- Can You Grow Anything in a Greenhouse?
A. Technically, yes, you can grow anything in a greenhouse, but there is no guarantee that everything will grow as well as it does in a garden. Wind-pollinated crops, such as rice, wheat, barley and rye, cold frame crops, such as carrots, and sunlight-loving vegetables, like radishes, will not grow too well.
Final Thoughts on Growing Vegetables Year Round in a Greenhouse
Growing vegetables all year round in a greenhouse is a fun activity that you can take up as a hobby to cultivate your own produce. Trust me when I say this, your meals will never taste better! Remember to:
- Choose a well-lit and warm site for your greenhouse.
- Sow and plant the right vegetables according to the season.
- Create ideal, growing conditions inside the greenhouse.
Did you like this guide? Let us know your thoughts in the comment section below and check out our blog section for more gardening tips!