Yield estimation for vegetable crops in greenhouse production

When planning planting in protected ground it is important to calculate the potential crop yield in advance. This allows one to estimate the profitability of the greenhouse and allocate the usable area correctly. The balance between the harvest volume and fruit quality depends directly on the planting density and adherence to agricultural techniques.

• Tomato harvest per plant — 5–10 kg
• Tomato planting density — 2 plants/m²
• Pepper and eggplant yield — 6–8 kg/m²
• Pepper and eggplant planting density — 4 plants/m²
• Watermelon and melon planting density — 4 plants/m²

Forecasting the yield of tomatoes, peppers, and eggplants

To calculate the maximum harvest of tall large-fruited tomatoes, it is optimal to place two plants per one square meter. A greenhouse with an area of 12 m² will hold 24 plants, which, with proper care, will yield from 120 to 240 kg of fruit. In practice, this is equivalent to one and a half to two buckets of tomatoes from each square meter. For novice vegetable growers, the average harvest is usually 2–3 kg per plant.

When growing sweet peppers and eggplants, the total mass of harvested fruits may turn out to be modest, as they are often picked while immature. These crops form compact bushes 50–70 cm tall, which should be tied to stakes when overloaded with fruit. In the short summer conditions of the Central region, 4–6 full-grown fruits manage to ripen on one plant. With regular and timely harvesting, each plant produces from 1.5 kg of marketable vegetables.

To effectively use the greenhouse area, it is important to adhere to the recommended planting rates. Excessive crowding reduces the light exposure of the plants and leads to the development of diseases. Below are the options for optimal placement of various crops.

Features of planning and shaping melons and gourds

When using vertical tying for vines and arranging two longitudinal paths, no more than four watermelon or melon plants per square meter are placed in a standard greenhouse. It is more practical to evaluate the productivity of melons and gourds in units rather than kilograms. One plant on average yields 1–2 fruits depending on the skills of bush shaping. Limiting the number of fruit sets allows for large, high-quality fruits and prevents the appearance of small fruits.

When shaping a melon or watermelon bush, several reliable pinching methods can be combined. The main stems are directed upward along strings for active development of the leaf apparatus, which nourishes the fruits. Lateral shoots without fruit sets are removed in a timely manner so that the plant does not waste energy on excess green mass.

1. Allow the vines to grow freely in all directions in a trailing manner at the initial stage, while there is still little green mass, and track the appearance of the first large fruit sets.
2. Carry out pinching of the lateral shoots and tie the main vine to a vertical support, based on the presence or absence of a fruit set on a specific plant.

Novice growers of melons and gourds sometimes prudently arrange an ordinary ground-level "melon patch" in their protected ground, and after confirming the required number of fruit sets (1–2 per plant), they subsequently only thin it out by removing excess lateral shoots and pinching all stem tips. With this method, plants are placed according to a 70 × 150 cm scheme, or about one plant per square meter. In that case, one can grow only 1–2 fruits per 1 m². The yield here can be increased by their size. These are the approximate figures. The yield also depends on the weather throughout the summer.

We can see that protected ground requires quite sparse planting, where sometimes even only one plant is placed per square meter. But in this case, even the accidental loss of one plant (suppose the stem was broken by carelessness) proves to be sensitive; it is a loss of almost 10% of the yield. One must not allow for any losses!

At the same time, our plants, since there are few of them, must be the very best of the entire sowing, select ones. Success depends not only on the skill of mastering the general agrotechnics of growing a "vertical melon patch," but also on the ability to obtain select plants and preserve them all throughout the growing season.

Sometimes soil burrowers pose a serious threat. To protect against larvae of the May beetle, the following measures are applied:

• all soil, including the outer perimeter, is pre-dug deeply and thoroughly;
• transplants are planted as mature as possible, as far as the crop allows;
• large containers are used whenever possible.

Then the roots of the plants are so extensive that they recover from mole cricket damage without losses.

A very serious danger is also posed by fruit cracking in watermelons and melons due to careless irrigation: fruit sets that have burst from an excess of soil moisture can be considered lost; they do not ripen and rot... As we can see, skill is needed everywhere.

In general, this is the formula for success: select the best plants from the sowing for transplants, place them at optimal distances, and, based on high general agrotechnics, obtain from each one the very high yield that they are capable of according to their cultivar traits. This way, it is possible to obtain a yield even higher than the indicated average figures for tomatoes, eggplants, sweet peppers, melons, and watermelons.

We still have a small greenhouse with all kinds of greens. Greens are easier to obtain, here we will have a "sure thing" — parsley is indestructible! — that it is even somewhat awkward to measure the mass of the harvest: the mass of "silage" depends only on irrigation.

Important. I suggest positioning each small greenhouse in a north-south direction so that direct sunlight enters when the door is open: then the produce becomes even healthier and comparable to open-field crops. It is precisely a short greenhouse that allows plants to receive a dose of the full solar spectrum for photosynthesis.

In conclusion of the chapter, let us say optimistic words that the indicated average yield leaves opportunities for creative growth. For someone who is setting up a transparent heat accumulator for the first time, eggplant, sweet pepper, watermelon, and melon are most likely completely new vegetable crops. This means that you will not understand them fully at once, and they will not reveal their full potential to you in the first growing season.

And it is normal when the harvest is modest in the first season, and in subsequent ones, taking into account identified errors and unused opportunities, it increases. In my opinion, this is better than the option of a "lucky" abundant first harvest (by coincidence, this happens to a beginner in a rare year of peak productivity for any crop, when conditions in the region are particularly favorable for it, and it gives an abundant harvest to everyone who just "bothered to stick a nursery plant in the ground").

And you can have no doubt that the significant expenses for the purchase will pay off. They will pay off with both yield and fruit quality, and with the comfort of working on your garden plot. Otherwise, you would have spent a rainy day in the country kitchen, but now you are tending to your plantings in a closed pavilion.