How to Grow Vegetables in the Greenhouse

Vegetables grown in your own garden will be the freshest. You can extend the growing season of spring and autumn by growing them in your greenhouse at any time. A greenhouse will allow you to control the temperature, humidity, water, and light, based on the needs of the vegetables. The type of vegetables to grow in your greenhouse will depend on your location and the temperatures within your greenhouse garden.

To succeed in cultivating vegetables, you must:


Planning involves preparation of the seeding area in the greenhouse. You need to determine how much space you require for the growing beds and the grow bags’ floor space. Ensure the greenhouse has enough space to separate spring plants from the summer vegetables you’re planning to grow.

Prepare the benches to create more room for seedlings. You can move some crops outside during the summer to create more room for planting other vegetables.

Planting the Seeds

Plant the seeds in the pots or starting tray. Read all the instructions on the seed packet and follow the instructions to plant the seeds, then make sure to buy high-quality seeds from a trusted source. Seeds of high quality will increase the germination rate.

Put two to three seeds in a pot containing the seed-starting mix and avoid using regular soil, as it may contain some diseases or may not be good for the germination of the seeds. Water the pots by using a sprayer or a meat-basting syringe, and gently water the pot without causing soil disruption. After watering, cover the pot with a plastic material to prevent it from drying too quickly.

The seed-starting mix provides the best conditions for germination of the seeds. It is best for drainage and has an excellent water-holding capacity. It also minimizes diseases, which can affect any vulnerable seedlings.

The containers should have an adequate number of holes to facilitate draining and ensure the seeds are not waterlogged. You should keep the seed-starting mix moist at all times to allow the seeds receive enough air and water, which are essential for the seeds’ growth.

Once you plant the seeds, place the pots or trays where there is direct sunlight. If the greenhouse has little sunlight, you can supplement it with artificial lights, such as a fluorescent light.

After the seedlings emerge, ensure the pots have good access to light and control the greenhouse temperatures according to the needs of the seedlings.

You can use a heated propagator to increase the warmth needed for the crop germination.

How to Grow Vegetables in the Greenhouse

After the seedling show up, remove the plastic cover and put them where they can access light, as they will need a lot of light and a frost-free environment to continue growing. You need to ensure some sections of the greenhouse are properly heated to provide enough of a warm environment for the plants’ growth, especially for tender vegetables.

Monitor the temperature of the greenhouse at all times. Some vegetables like broccoli grow within 50°F to 70°F (10°C to 21°C) during the day and between 45°F and 55°F (7°C and 13°C) at night. Warm-loving vegetables can tolerate day temperatures between 60°F and 85°F (16°C and 29°C) and 55°F to 65°F (13°C to 18°C) for night temperatures. Therefore, warm and cool vegetables may not survive in the same greenhouse temperatures, so you should always choose what to grow in each greenhouse and when.

You should also start the fertilization of the growing seedlings after every week. Organic fertilizers are highly recommended because they can provide a wide range of nutrients and micronutrients to the seedling.

If there are more seedlings in the pot, you can thin out the excess seedlings with scissors once the seedling has grown two sets of leaves. Always thin out the weakest one.

Each pot or container should have a single seedling for it to grow well, so continue to water the seedlings to allow them to grow.

Transplanting the Vegetable Seedlings

You need to plant the vegetable seedlings in their final location once they’re well rooted in the soil. You can do this using large containers or growing bags to plant the crops. Offer extra care to the newly transplanted vegetables and ensure they’re shaded from direct sunlight for a day or two or until they get established.

When transplanting the vegetable plants, make sure you place the pots with the tallest plants on the shelves at the back.

Ensure there is some space between each vegetable plant and water the vegetables regularly or when necessary. You should not leave the top soil dry for too long.

You must give vegetables like cucumbers and melons support as they climb up. You can tie one cucumber tree to another to give them more strength and to allow them to support one another. To support cordon tomatoes, tie them up with strings or canes.


Make sure you water the vegetables well and daily, as uneven watering can affect some of the vegetables. For example, if certain sections of the tomato beds are not well-watered, it can result in rotting.

Ensure the greenhouse is well-ventilated and there is enough light inside to aid in the growth of the vegetables. You can install automatic vents or use the manual vents to keep the room well-ventilated.

You can open the door of the greenhouse or its windows to let fresh and cool air flow inside, which will help regulate the greenhouse’s temperature. If there is too much heat lost in the greenhouse, you can reduce the heat loss by insulating all windows and doors.

If you have planted warm-loving vegetables such as cucumber or okra, make sure the vents remain closed and increase the humidity in the room. This makes certain that no moisture is retained, which can damage the vegetables. You can also partition some parts of the greenhouse with a clear, plastic material.

Make sure you keep the greenhouse clean at all times. Investing in bubble wrap insulation for your structure would be an excellent idea to address this concern.

If you’re using a heated greenhouse, install a thermostat to maintain the greenhouse’s temperature. This will ensure the minimum nighttime temperatures do not drop below the expected temperatures for the plants’ growth. You should also install a two thermometers to monitor the minimum and maximum temperatures within the greenhouse. One thermometer will measure the temperature inside the greenhouse, whereas the second thermometer will measure the outdoor temperatures.

Always remember to tie up the vegetables to provide support for any new growth, especially if you are handling tomatoes in the greenhouse.

Be alert and watch out for pests, bugs, fungi, and any other diseases that can affect the plants in the greenhouse. If a fungal disease infects your garden, you should consult with professional services on the possible insect repellents to use.