Like tomato, cucumber, or pepper, also eggplants are very popular amongst greenhouse gardeners to grow in their greenhouses. Growing eggplants in a greenhouse is simpler than you think! Therefore, I want to show you in this in-depth greenhouse eggplant growing guide, how you can start growing eggplants in the greenhouse.
If you first want to step up a greenhouse the right way, then also take a look at: Setting up a greenhouse – what to know before starting
The origins of eggplants
Even though the homeland of eggplant is referred to as India, China, wild species are also found in Africa. The eggplant was transported to North Africa via Egypt, and then to Spain by the Arabs and to Europe via the Balkans by the Turks. Eggplant lives as a shrub for a few years in tropical climates, while it lives for 1 year in cool climates.
What botanical properties do greenhouse eggplants have?
When the eggplant seed germinates, it forms a pile root, but the roots that occur in the following stages develop as taproot and take the fringe rooted structure. Side roots can spread to a depth of 80-100 cm and around.
70-80% of the roots go down to 5-40 cm deep. Numerous branches occur on the roots and there are absorbent bristles on the branches.
When an eggplant seedling has 5-12 leaves, branching occurs. After 5-12 leaves reach their real size, the growth tip at the shoot tip changes from vegetative direction to generative direction and turns into a flower bud. In the meantime, a new growth end of the leaf next to the flower is formed and continues and creates a new side branch. In the meantime, a new shoot bud is formed next to the flower bud in the main exile and it forms a second side branch by driving. This cycle continues every 2-4 leaves.
Body
The eggplant body has a strong structure. There are feathers on the trunk and leaves. It consists of invisible knuckles on the body.
Leaves
Its leaves are small, narrow, thin, and long or large and wide. The leaf edges are straight, as well as fragmented, slightly slit. Its edges are generally straight. Femininity is not seen much. The leaves and stem are green in color. In some varieties, the color turns purple, or bruises are seen in places.
Flowering
Flowering depends on the season the plant is grown. In the warm period, flowering occurs earlier. The first bloom usually occurs 70-90 days after sowing. The first flower occurs after 5-12 leaves.
Fruits
Eggplant fruits can be long, thin, pointed, long cylindrical, blunt or pointed, long egg, round, flattened round shape. Fruit length is very different. It is approximately 20-30 cm. Fruit diameter is 2-6 cm in long varieties and 8-12 cm in round varieties. Fruit weight is 50-400g. Weight goes up to 500-1000 g in round varieties. 10-30 or even more fruits can be taken from a plant.
The best eggplants to grow in the greenhouse
If you want to grow eggplants in the greenhouse, you have a few possibilities. The eggplant varieties differ in the shape and size of the fruit. Here are some examples of eggplants you could grow in your greenhouse:
- White Sword is a variety with ivory-colored eggplant. They become up to 20 centimeters long. The variety is only suitable for the greenhouse.
- Violetta di Firenze is very popular in eggplant society but needs a lot of warmth. The meat of the ribbed fruit melts on the tongue. The distinctly striped ‘Pinstripe’ variety also grows best in the greenhouse.
- Tskoniki, a traditional variety from Greece, is known for its mildly sweet taste.
- Kaberi supplies countless mini aubergines with deep purple skin and can be grown on the balcony or in a sheltered spot in the bed
- The eggplant variety Ivory, on the other hand, is ideal for pot culture. The creamy white, thin-skinned fruits are perfect for Italian aubergine casserole (Parmigiana).
Growing periods in greenhouse eggplant cultivation
Eggplant cultivation in our greenhouses is carried out as a single crop and spring cultivation. Autumn production is not preferred much. The reason for this is that the outdoor production in summer is not economical because it continues until the end of autumn where the climate is mild.
The growing periods for spring and single-crop cultivation is listed in the table below:
| Growth Period | Seed Planting | Planting | Harvesting Period |
|---|---|---|---|
| Spring Cultivation | October – December | January – February | March – July |
| Single Crop Cultivation | August | Sep 15 – Oct 1 | November – June |
What are the temperature requirements for growing eggplants in a greenhouse?
The eggplant is a heat-loving plant. Although seed germination starts at 12 ° C, the ideal germination temperature is 19-26 ° C. The temperature at which the plant can survive biologically is between a minimum of 10 ° C and a maximum of 35 ° C. During the seedling growing period, the night temperature should be 16-19 ° C and the daytime temperature should be 19-22 ° C.
For good development and yield in the greenhouse, it is necessary to keep the temperature at 17-22 ° C at night and 22-27 ° C during the day. When the difference between day and night temperatures is 5 ° C or a little more, the fruit set and development of the flowers accelerate. If the soil temperature is kept at 15 ° C, plant growth will be strong.
Lighting
It is a light-loving, long-day plant. It takes 14-16 hours of day length. High light intensity is required for high efficiency. Vegetative growth increases in low light conditions and fruit binding become difficult.
How to prepare the soil to grow greenhouse eggplants
At first, fertilize the soil where eggplant will be grown. A deep release is made in the fall. You can level the soil by pulling a rake with a spring-out plow. After that, bobbins or pans are prepared according to the irrigation systems to be made in the growth stages of the eggplants. Space between the rows depends on the growing strength of the variety and the soil. Normally, it varies between 0.70-1.00 m depending on the situation. On the line usually 0.50-0.60m distance is left.
Growing seedlings for greenhouse eggplants
If you want to produce the seedlings on your own and do not want to buy them, you can plant seeds directly in the growing container. As the seedling growing container, you should prefer a multi-cavity plastic/foam tray (multi pot-viol). Fill this with a small amount of mortar so it is easier for you to transport.
To grow eggplants in the greenhouse, one seed is planted in each well of the multi-eyed tray, where the seeds germinate, the seedling grows and is planted in the greenhouse. Since it is clean, you can use nutrient-added peat or 2 parts peat and 1 part perlite mixture as mortar.
The number of seeds in 1 gram varies according to the variety, there are 180 seeds on average. The planted seeds should be covered with a 0.5 cm thick cover mortar. After planting, depending on the climatic conditions, germination appears after 8-15 days.
Possible problems in seedling cultivation
High temperatures and pests can be a problem in seedling cultivation for a single crop period. In the spring period seedling cultivation, low temperature, light, and high humidity may cause problems.
Seedlings should be grown on benches if possible. If this is not possible, a nylon cover should be laid between the ground and the seedling growing containers. Thus, the mortar is kept warm and diseases and insect damage that can be transmitted from the ground are prevented.
Planting the seedlings
Depending on the seedling growing container and the environmental conditions provided, your seedlings are ready for planting approximately 40-60 days after sowing.
Preparing the greenhouse for planting eggplants
The greenhouse to be produced is first cleaned of all the old plant residues and if the greenhouse is used for growing for a long time, the plow base, which consists of continuous processing at the same depth, should be broken with the subsoiler and washed abundantly with irrigation in the form of ponding.
To grow eggplants in the greenhouse and eliminate disease, harmful, and weeds in the soil, use the solarization method. Begin to fertilize at this step.
If you want to know, how you can produce organic fertilizer at home, also take a look at: How to make organic fertilizers at home
Planting eggplants in the greenhouse
Planting rows should be prepared in a north-south direction. Sewing can be done flat or in the form of high pillows. Planting time is between September-October for single-crop cultivation and late January-mid February for spring period cultivation. Planting should be done in double rows. For single crop cultivation, it is planted with 100 cm double row spacing, 60 cm row spacing, 50 cm row spacing (100X60X50 cm).
As the weather will warm up and the amount of light will increase in the spring period, the distances are reduced a little more. In this period, 80 cm double row spacing, 50 cm row spacing, 50 cm row spacing (80X50X50 cm) are planted.
How to hang greenhouse eggplants
After the plants are planted in the greenhouse and the plants are already 30-40 cm tall, a plastic rope is attached to the lower part of the body of each plant or a finger gap is tied. Furthermore, the trunk is twisted clockwise and hung on the hanging wire above. The bottom shoots and the side shoots emerging on the main stem should be cleaned until the branching occurs. A few more shoots from the branching point are allowed to grow as stems. In this way, your eggplants will grow with 2, 3, or 4 main stems.
But in terms of aeration and lighting, you should prefer 2 or 3 main body cultivation. For other shoots or shoots left as the main body, tie them with a hanger rope from the bottom and place the above hanging wire in a way that it does not interfere with the other stems and does not disturb lighting and ventilation. Once a week, the plants are wandered around and the ends of the main stems left are wrapped around the hanger rope.
How to prune eggplants grown in greenhouses
The body of the eggplant has a woody structure. While usual varieties are 60-100 cm in length, hybrid varieties used in the greenhouse grow up to 2.5-3 meters. While the plant initially grows as a single stem, branching begins after the 4th or 5th node, and shoots develop on the side branches. Greenhouse eggplant varieties should be hanged and pruning practices should be done due to this botanical structure. The reason is to increase illumination and aeration, to apply cultural processes easily, to balance vegetative and generative development, and to increase fruit quality.
The following pruning is done in greenhouse eggplant cultivation:
- Shoot pruning
- Flower pruning
- Leaf pruning
- Collecting petals on the growing fruit
Shoot Pruning
With the growth on the main stems of the hanging eggplant, lateral shoots are formed continuously. These side shoots should be pruned for a productive and high-quality product and to enforce lighting and aeration. Pruning of these side shoots is done by removing the ends of the side shoots after the 1st or 2nd leaf after the flower is formed. After the fruit is taken from these side shoots, you have to cut the shoots that come out from the bottom and clean them.
Flower pruning
Flower pruning is another pruning that should be done without interrupting flower pruning in greenhouse eggplant cultivation. In eggplant, flowers occur singly or in clusters. Among the flowers that are formed in clusters, the ones with thick stems create quality fruits of size and color specific to the variety. By not doing that, the fruits will be smaller and even discolored.
Leaf pruning
Eggplant is a vegetable that likes strong leaf pruning. You should remove yellowed, diseased, old, physiologically dysfunctional leaves on the fruit. Moreover, removed branches and the lower part of the plant and some leaves that prevent sunbathing are also part you can take care of.
Collecting petals on the fruit
Normally, in flowers that bind fruit, it is seen that the petals fall from the fruit end to the ground and fall off, sometimes they do not fall and remain at the end of the growing fruit. It is necessary to take the petals (purple flowers) remaining on the fruit, especially in cold and humid periods. Because they attract moisture and cause disease factors. In particular, they help the spread of gray mold (Botrytis) disease.
Watering greenhouse eggplants
The soil should not be too dry or too wet. Irregular changes in soil moisture can cause flower loss and uneven growth. Eggplant loves water very much. Regular watering should be done during the breeding period. Ideal watering is the so-called drip irrigation. After the seedlings are planted in the greenhouse, watering should be avoided unless it is necessary until the first fruits appear on the plants. Later, the water need of the plant should be met at frequent intervals.
Harvesting the eggplants
Harvest starts in 3.5 months to 5 months after planting, depending on the environmental conditions we provide to the plants. The better the environmental conditions are provided, the better the plant development and the sooner it comes to harvest.
It is very difficult to determine the harvest maturity time for eggplant at the beginning. Unripe fruits are very dark purple, while overripe fruits are pale purple. The period between these two is the full maturation of the fruit, during this period it must be harvested. During this period, a slight discoloration is observed at the tip of the fruit. However, this discoloration can also be seen with the effect of low temperature in unheated cold greenhouses, and should not be confused with this.
Harvest should be done once a week. During harvesting, a sharp knife or scissors should be used, part of the fruit stem should remain on the fruit. During the transportation and packaging of the harvested fruit, it is necessary to pay attention to the very hard sepals (calyx) on the fruit stem and stem part not to damage the other fruits.
