How to Grow Vegetables Year Round in a Greenhouse

Did you know that growing vegetables all year long in a greenhouse is possible? It’s true! You need to keep a few things in mind if you want to be successful at vegetable growing in a greenhouse year-round.

When growing outdoor crops, you are at the mercy of the weather. If there is a cold snap in the early spring or fall, your plants may get killed. However, by growing your crops in a greenhouse, you can extend your growing season and grow vegetables all year round.

In this article, we’ll give you tips on how to grow vegetables in a greenhouse year-round.

What is a Greenhouse?

First off, let’s make sure you understand how a greenhouse works. Greenhouses are buildings designed primarily for growing plants out of season. A greenhouse is a structure made out of transparent material (usually glass or plastic) used for growing plants.

The benefits of growing vegetables in a greenhouse are numerous. Greenhouses protect plants from bad weather conditions, like strong winds, heavy rains, or frost.

Your growing season can be extended, and you can even have access to fresh veggies through the winter and into the early spring if you have a greenhouse in your garden, which is an excellent advantage for producing vegetables and creating your vegetable garden.

How to Choose the Right Greenhouse

When it comes to choosing a greenhouse, there are a few things you need to take into consideration.

First, you need to decide what size greenhouse you need. It will depend on the space you have available and the number of plants you want to grow. Second, you need to choose the right location for your greenhouse. It’s essential to choose a spot that gets plenty of sunlight so that your plants can grow properly.

Third, you need to decide what type of greenhouse you want. There are two types of greenhouses to choose from: an attached greenhouse and a freestanding.

Freestanding greenhouses are not attached to any other structure, while attached greenhouses are typically built onto the side of a house or another building.

See Related: Best Wooden Greenhouses: Top Ideas You Should Try

The Basics of Setting Up a Greenhouse for Vegetable Growing

Once you’ve chosen the right greenhouse for your needs, it’s time to set it up for growing your vegetables. Follow these steps:

Step 1: Preparing the Greenhouse Frame.

Your greenhouse frame needs to be sturdy, so using a PVC frame might not be a good idea if you don’t know what you’re doing. 

If you decide to use PVC, at least ensure one end can detach from the rest of the frame so you can easily move it or use it again another day without damaging all those expensive materials.

We must take the time to make our greenhouse frame sturdy, regardless of material.

• Construct the base from PVC, wood, concrete, or brick. The base must be able to support the weight of the greenhouse.
• Install support beams. The length will vary depending on your greenhouse size but should be around 3 feet high to prevent damage from strong wind gusts.
• Install 1×2 beams 
• Install door. If you live in an area with lots of strong wind gusts, you must ensure this door is secure and can handle pressure.
• Install roof out of wood, metal, or plastic. It needs to be strong and handle the weather without damaging the structure. You want it to be able to support the weight of the greenhouse.

See Related: Best Mini Greenhouses | Portable Options to Buy

Step 2: Select What Vegetable to Plant

When planning to grow vegetables in a greenhouse year-round, selecting vegetables that will thrive in your greenhouse gardening and greenhouse production conditions is important.

Some vegetables ideal for growing in a greenhouse include tomatoes, peppers, cucumbers, and herbs. These vegetables can be planted in pots or soil, and they need plenty of sunlight and water to grow successfully.

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Step 3: Prepare Containers and Soils

After you’ve decided on a vegetable, select your containers and soil. To drain any excess fluid from the container, it will also need to be large enough for your plants to grow freely.

The kind of grow container you choose is dependent on the type of plant you select and whether or not you’re planting it straight into the dirt. If you’re just starting, potting is the ideal option because there’s no need for structure.

You may choose the size, shape, and color of the containers you want. Pots are available in many different materials and styles. The presence of fibers, plastic, and biodegradable wood makes a significant

See Related: How to Choose the Right Greenhouse Sizedifference.

Step 4: Preparing the Soil for Planting

Using soil that has been tested is not recommended because it may be too rich for greenhouse plants or vegetables that you want to grow yourself. Try starting with a base that isn’t mixed with anything yet.

This way, we know what’s going into the ground where our food is growing.

If you’re starting with soil from another part of your home (like under your garden), ensure it doesn’t have any chemicals added like pesticides, herbicides, etc.

Plants can absorb these chemicals and may stay in the plant once we harvest and eat them. Also, remember that water is approximately 80% of the weight of the Earth’s crust.

So, fertilizers and chemical nutrients from fertilizer can easily seep into the ground with too much rain.

• Get an old compost bin
• Put soil in the compost bin and mix thoroughly without adding any new material
• Let the mixture dry completely before planting.

See Related: Best Greenhouse Plastic Sheets for Protection

Step 5: Planting Seeds/Seedlings

Once you have everything set up, including your greenhouse structure, soil, tables to work on, and seeds or seedlings that are properly germinated, we can now start planting our seeds and seedlings.

Organize Your Seeds

Before planting the seeds/seedlings, you want to grow, organize them first. If you’re doing more than one type of plant, I recommend using a separate table for each different one.

Plant

Place them in your greenhouse as in any other indoor planting environment. It is best to put each plant into its pot.

When planting, make sure the soil you use is well mixed and doesn’t have any excess chemical nutrients or fertilizer.

Water Plants as Necessary

There is no need to flood the plant area. Believe it or not, excess water can cause many problems and diseases that spread quickly through too much humidity. Fungi and germs require water to spread and infect plants.

Too much water with poor drainage may also cause mold growth in the soil. Mold is not good for our health and affects the harvesting and consumption of crops. Mold can also make animals sick, so it’s important to remember.

A common plant disease resulting from water is root rot, which can kill a plant in a short time. Signs of root rot include wilting, weaker leaves, and lack of vigor.

Irrigation System Ideas

Make sure you have an effective way to keep plants moist. Otherwise, they may dry out too quickly or not get enough water.

Planting containers are usually watered by either a drip irrigation system or the bottom. If you have shallow roots, it’s best to water by the latter method.

A drip irrigation system is ideal since it can water both the top and bottom roots at optimal times. It’s also much more convenient.

See Related: 6 Best Geothermal Greenhouse Systems

Step 4: Best Light Conditions

In addition to water, our plants must have optimum light from a natural or artificial source.

Natural light is preferred but not always available. To create a greenhouse environment for plants, we need to have the right combination of heat and humidity.

If necessary, you can also use products like grow lights at night since plants absorb more light energy than the heat and create a t for the plants. So, it’s better to have a source of light that emits more energy, like grow lights. This makes heat-loving plants and other crops grow healthy and grow faster.

For example, the common problem is that the lights are installed too close to the plants. If this happens, the leaves may burn and turn brown.

It happens because strong lights produce a strong electromagnetic field emitting ionizing radiation. Ionizing radiation can zap the electrons in molecules like DNA, which is what damages plant stem cells. It’s not advisable to use black lights since they emit this type of radiation. The best lights are blue and red lights.

LED lights can work, but because they have a weaker magnetic field, it’s possible to install them too close to plants.

Supplemental lighting may also be the reason why plants are growing slowly at first. They need time to acclimate to the new environment, so they grow slower at first.

With time and patience, you will start seeing results as your plant grows.

Lighting in a Winter Greenhouse

Come in through the windows and provide enough light for your plants. However, it will get dark early at night, and you will need to provide artificial light for your plants.

There are many different types of artificial lights that you can use on top of the temperature in your greenhouse is also important. In the winter, you will want to ensure the temperature does not drop too low.

One way to do this is to use a space heater. You can also insulate your greenhouse with a tarp or bubble wrap to help keep the heat in.

See Related: Best Insulation for a Greenhouse

Step 5: Maintaining Ideal Temperature

Before you install the greenhouse, make sure you have set everything up beforehand. Your greenhouse must provide an ideal temperature and light conditions for your plants to survive and grow.

Temperature

You’ll want to monitor the temperature daily. Even if you have an automatic thermostat, it’s better to monitor it yourself because certain conditions cannot be accounted for.

Aim to keep the temperature between 70 and 80 degrees Fahrenheit with an ideal temperature of about 75.

Humidity

Plants’ quantity of moisture and soil moisture varies by species and climate. When a dry house exists, it will make sense to grow plants in dry conditions that will be less exposed to humidity than dry climate plants do when they grow dry.

It’s also important to monitor and maintain your greenhouse humidity levels. We don’t want the humidity to fall too low. Low humidity may result in small leaves and dry conditions that make the plants more susceptible to drying out. In this case, we can consider adding a humidifier.

When the humidity is too high, we can experience problems with plants wilting and mildew. We can control humidity by how good the ventilation is when there are fluctuations in air temperature. As we space out the plants adequately, ventilation improves.

Avoid leaving puddles of water on the ground, or it will increase humidity and breed mosquitos.

The greenhouse must also be well ventilated to prevent mold and decrease humidity. The air circulation also keeps the greenhouse cool during hot days and warm during cold nights.

Venturing

In a greenhouse with a warm environment and temperature, caution must be taken to ensure proper ventilation. The shutters are down, and the windows are open, allowing easy ventilation. It provides excellent ventilation, allowing the forecasted temperatures to be higher than 40F (4C).

Plants should be kept on the cooler sides in the spring, early summer, and fall to promote healthy development. If your greenhouse becomes too hot in late autumn or winter, delicate growth develops that can be damaged as temperatures drop.

Step 6: Add a Heating System

When growing vegetables year-round in a greenhouse, one important factor to consider is the addition of a heating system. A heating system will help ensure that your greenhouse plants stay warm and healthy, even during the year’s colder months.

A greenhouse can be a great way to extend the vegetable gardening season for your vegetables, but if you live in a cold climate, you may level up your unheated greenhouse.

There are various heating systems available, so be sure to choose one that will meet your needs. Consistent heat is crucial for growing greenhouse vegetables year-round in a greenhouse, especially in the winter months.

If your plants are exposed to sudden temperature changes, or you have an unheated greenhouse, they will likely experience stress that could inhibit growth or even kill them.

A heating system will help maintain a consistent temperature inside your greenhouse, ensuring that your plants stay healthy and thrive.

Step 7: Feeding Your Plants

Use all-purpose plant fertilizer for your plants every 2-3 weeks. You can spray it on or pour it around the base of your plants, making sure to avoid getting any on their leaves.

A little TLC will help them grow and look better over time.

Just remember that too much fertilizer is not good for anything. If someone in your home has asthma or other respiratory conditions, it could be worsened by chemicals in the air around them.

See Related: How to Utilized Greenhouse Bees for Pollination

Step 7: Removing Unwanted Plants and Root Systems

It’s best to keep weeds out of the greenhouse since they will only take away important nutrients and water from your plants.

We must remove weeds quickly so they don’t have the chance to break their roots and regrow in different spots.

Root systems can also become overcrowded, which will result in less-than-ideal plant growth. You can also remove unwanted plants by hand if it’s too difficult to find the main root system.

Herbicides also work well, but you should always spray in the late evening or early morning to avoid burning or frying your plants.

Transplanting

Transplanting is a great way to avoid overcrowding because it helps plants get more nutrients and light.

When transplanting, you must be gentle with the plant to avoid damaging its roots. You’ll want to dig a hole about 2-3 times wider than the plant’s root system.

Hold the plant by its stem gently and carefully drop it into the hole, then cover the roots with soil.

Avoid transplant shock by ensuring you have watered the plant well before and after moving it.

Step 8: Preventing Pests from Harming Your Plants

Now that we have our seeds planted, we must protect them until a good harvest. Just because your plants are in a greenhouse does not mean they are free from pests. Some typical greenhouse pests include:

Spider mites

These mites are tiny, and most come out at night. They will suck the juice out of your plants until they are dry and withered.

Whiteflies

These little white bugs love to feed on plant juices, too. The problem with them is that they spread extremely quickly. You’ll see these flying around in swarms if you don’t take care of any problems early on before they become an infestation.

Caterpillars

You’re more likely to get this type of pest when using soil from outside your home because it could have eggs hidden in it without you knowing about it ahead of time. If you find any caterpillars, make sure you pick them off one by one or use pesticides/insecticides to treat the greenhouse as a whole.

Aphids

Aphids come in different colors and love to suck the juice from plants, so they wilt and die. They can multiply very quickly, too, so it’s important to get them under control as soon as possible.

Mealybugs

These pesky pests hide under leaves and then transfer over to other parts of the plant where you won’t see them until you see yellowing leaves or a powdery-looking substance on your plant.

If you leave this untreated early on, it will spread like wildfire throughout your greenhouse.

Fungus gnats

These gnats are annoying as they love to feed on plant roots and lay their eggs there. The result? Your plants will have stunted growth, yellow leaves, or die.

Luckily, there are several ways to prevent pests from ruining your plants.

• Cover the greenhouse with a fine mesh or plastic.
• Rinse the greenhouse before adding new soil to avoid bringing any unwanted pests from the soil you used before.
• Replace old soil periodically. New organic soil may help reduce the number of bugs in it.
• Add floating row covers over plants when they are about 4 inches tall and leave them on until harvest to protect against small pests that hide under leaves.
• Use Neem oil for pest control, which comes from neem tree seeds. Only use 5ml per gallon of water mixed before spraying directly onto the plant. If you spray during the day, the sun will burn the leaves. Spray in the evening when it is cooler.
• Tobacco tea can also help prevent bugs in the greenhouse. Fill a clean trash bag with water and add 1-2 handfuls of tobacco. Tie the bag shut, but not too tight. Steep for three days in the sun, and then lightly spray on the leaves of your plants.
• If you find a bug, pick it off by hand or use pesticide to treat the greenhouse.
• Use pest traps. Get some that are either sticky or use natural chemicals to attract the pests away from your plants.

See Related: Best Greenhouses for Cold Climates

Step 9: Harvesting Your Crops

It’s hard to pick a perfect time to harvest your produce. So whenever you see a ripe fruit or vegetable, plan to harvest it.

If you grow a tomato, for example, you should see some changes in color from green to dark red or orange before it is time to harvest.

Before starting any crop, ensure you know how it will look once it is fully ripe. For example, a watermelon will turn a darker green before it ripens, and a tomato turns from green to red or orange.

Whenever you pick fruits and vegetables, ensure you do not damage other ones nearby that are still growing.

See Related: Best Glass Greenhouses in 2023

Step 10: Cleanup After Growing Cycle

It is time to start over again and create a new greenhouse to grow the following year. Start by cleaning up all your old plant material, taking out old boards or whatever is in there that you will not use.

Then clean the greenhouse before adding soil, fertilizer, and new plants for your next growing cycle. You should start your next cycle 4-6 weeks before your greenhouse’s last frost of winter.

Best Types Vegetables that can be grown in a greenhouse year-round

Most vegetables grow well inside a greenhouse, especially items like tomatoes, peppers, eggplant, and cucumbers. You can plant root vegetables like carrots, beets, and turnips, as well as leafy greens like kale or Swiss chard.

The vegetables with the highest yield in a greenhouse environment include:

Spinach and Leafy Greens

When we grow Popeye’s favorite vegetable in our greenhouse, we get a clean, leafy green free of debris and dirt. This crop can grow very quickly as well.

Tomatoes

Because they are grown indoors, tomatoes don’t have to deal with the elements outside and can develop into a rich source of nutrition. These are the most common greenhouse vegetable to grow. 

Beefsteak, cherry, grape, and tomatoes on the vine are available to grow in your greenhouse.

Microgreens

Microgreens are an excellent source of vitamins and nutrients, which is why these fresh greens and salad greens make great kitchen additions to any home or restaurant. They are easy to grow in a greenhouse environment.

Cucumbers

I love eating cucumbers in my salads. Luckily, they also produce fruit and a bountiful harvest in a greenhouse. These are also very profitable to grow for sale but don’t have a long shelf life after harvest.

Herbs

There are several types of hardy herbs we can grow in a greenhouse. One of my favorites is basil. Grow it in your greenhouse for use in all sorts of dishes, including Italian dishes, pesto, and even fresh summer salads.

I love mint in my iced tea, but it does get out of hand quickly. Luckily, growing mint in your greenhouse will secure it in one area with proper drainage.

Peppers

Peppers are another delicacy that we may grow in a greenhouse with some effort. Grow bell, chili, and paprika peppers.

Green Onions

Green onions are a great vegetable to grow in a greenhouse year-round. They are small and easy to grow, and don’t take up much space. They taste great and can be used in salads, soups, or other dishes.

These are not the easiest crop on the list to grow, but if you master them, they can yield a good profit.

See Related: What are the Commercial Greenhouse Construction Costs?

How Does Climate Affect My Greenhouse?

Temperature and humidity levels inside your greenhouse will be higher than outside as sunlight heats the air and tender plants release moisture. Also, if you live in an area where it snows, take care not to build your greenhouse in a place where snow might accumulate and damage the structure.

Finally, if you live in an area with lots of wind and rainfall, make sure you add some roofing for your greenhouse to protect against any damage from strong gusts of wind or water.

If you live somewhere like Alaska, Canada, Greenland, or Sweden, where it gets cold in the winter but warmer during spring and summer, your greenhouse will be at its prime use to grow food during the warmer months.

For veggie growers in places like Australia or an area with hotter temperatures, protect your greenhouse from the elements. Use it to keep your greenhouse vegetables and plants safe during the hot summer.

FAQ

Related Resources

• Greenhouse Cost Guide
• Best Greenhouse Lights for Plant Growth
• Best Indoor Greenhouse With Lights