Sowing Vegetables in the Greenhouse

Sowing Vegetables in the Greenhouse

In the greenhouse, we pre-grow 90% vegetables. We sow these vegetables in separate boxes and pots. Apart from pre-growing vegetable seedlings, we use the greenhouse for growing early lettuce, radishes, and turnips. We force chives, parsley, and other herbs in pots. Fresh herbs are very healthy, rich not only in vitamin C, which the human body needs immediately after winter.

If we have a level in the greenhouse, which can be formed by, for example, just a board placed under the roof, we can place cacti and exotic plants on it. In the greenhouse entrance, you can grow palms and citrus plants. It can serve as a winter garden.

Sowing vegetables in boxes, cups, and pots is done very early in spring. Some crops can be sown as early as February. Boxes and cups for sowing must be clean, disinfected, to prevent mould and pests from entering the greenhouse. When sowing seeds, we follow the instructions on the packets of individual plants. Some small vegetable seeds should not be covered with another layer of soil - for better germination and heat retention, they can be temporarily covered with newspaper.

Sowing Vegetables in the Greenhouse

When sowing vegetables, we always follow the advice on the packaging in which we purchased the seeds. We improve the soil for sowing with compost, peat, and we can aerate it with sand. You can also purchase substrate specifically designed for sowing vegetables.

In boxes placed in the greenhouse, we most often sow these types of vegetables in February:

• early brassicas
• early lettuce
• celery
• peppers
• tomatoes
• herbs

In the greenhouse, we can prepare seed sowing of melons, cucumbers, and sweet corn. We grow these seeds in propagation trays or cups. This way we pre-grow smaller quantities of seedlings. This is because cups take up more space in the greenhouse than fully utilised boxes. Watering - must be gentle in the greenhouse. We recommend choosing a suitable watering can and watering plants with lukewarm water. A barrel with rainwater can be placed directly in the greenhouse.

Ventilation - in very sunny weather, we recommend ventilating the greenhouse. Early brassicas and lettuce thrive at temperatures of 16-18°C. More heat-loving plants (tomatoes, cucumbers, peppers) - thrive at temperatures of 22-25°C.

Pre-grown Vegetable Seedlings

We recommend pricking out vegetable seedlings grown in a greenhouse. Pricking out is done as soon as the seedling develops its first cotyledon leaves, or as soon as it develops its first true leaves. We prick out into deeper trays. This way we get better quality seedlings! We recommend adding peat to the trays. This helps the pricked out seedlings to form a root ball more easily (e.g. tomatoes are pricked out 10 cm apart). When pricking out plants, we discard weak, elongated, or droopy seedlings.

Plants can also be pre-grown individually, for example in peat pellets, which we place in plastic cups. Plastic cups retain moisture better than terracotta pots. If you have surplus terracotta pots and want to use them for pre-growing, it is recommended to sink them mostly into the soil/substrate so that moisture is more easily retained.

TIP - when pre-growing cucumbers (and melons) in a greenhouse, fill the cups only halfway with substrate. As the seedlings gradually grow, add substrate gradually up to the rim. Before sowing, let the seeds swell in lukewarm water.

Germinated plants from greenhouses should be gradually hardened off. Before planting them in the bed, it is recommended to place them in a cold frame for some time, where the plants get used to lower temperatures.

Try to use the greenhouse as efficiently as possible! Use it only for pre-growing quality vegetable seedlings. In May (after the Ice Saints), when you clear the greenhouse, as you transplant most of the pre-grown vegetables to the outdoor bed, use the greenhouse for growing peppers, cucumbers, salad cucumbers and tomatoes.

During September, the greenhouse can be sown again - with radishes and lettuce. In autumn, you can still grow cauliflower and Chinese cabbage in the greenhouse.

The greenhouse can cool down in early spring and autumn months. This also happens on cold nights and in windy weather. To prevent temperature fluctuations, we can temporarily use polyethylene film for insulation.

The air between the glass and the film creates the necessary thermal insulation.

Greenhouse Construction

If you are considering building a greenhouse, pay attention to these factors:

• location - choose an unshaded, sunny spot
• heating - if possible, build the greenhouse close to your house
• construction - in too open an area, sink part of the greenhouse into the ground

Before construction:

• make a sketch - plan the dimensions of your greenhouse. What material the greenhouse structure will be made from. Where the doors will be and how wide they should be (so a wheelbarrow can fit through, for example)
• greenhouse heating - whether it's necessary or not. Heating is useful if you're considering year-round growing or overwintering plants. From October onwards, sunlight decreases and growing vegetables at all costs even in winter may not be efficient
• rooms - if you have space for a long greenhouse, plan a corridor (vestibule, entrance area) that will protect plants from direct penetration of cold air

When building a greenhouse, also pay attention to insulation, covering or shading the roof.

Do you have experience building a greenhouse? What plants do you most often sow in your greenhouse? Share with friends on Facebook!

Author: Hana Michalíková