Most greenhouse owners are in many ways very traditional in their choice of plants. We tend to choose traditional vegetables, like tomatoes, peppers, and cucumbers. A few years back we, at Spirekassen, started to grow aubergines in the greenhouse. Once you have tasted your first homegrown aubergines, there is no way back! They taste fantastic and are far more intense, than aubergines bought in the stores.

The aubergine (Solanum melongena) is a perennial plant, however, in countries with cold winters, it is grown as an annual plant. The aubergine is far from robust in countries with real winters. It is not finally clarified where the aubergine originates from. It is known that the aubergine is native to India, however, the aubergine has a long history in Africa and Asia as well.

 

There is a long list of varieties. The height of the different varieties can vary between 40 – 150 cm. The size and appearance of the fruits differs a lot, depending on which sort you choose to grow.

You might be overwhelmed by the beautiful violet flower the first time you grow aubergines. If you look closely, you might see that the aubergine flower is built exactly like the potato and tomato flower. The aubergine, tomato and potato belong to the same botanical family, the night shade family. Common for the members of the nightshade family is the toxin solanine. The aubergine flower and leaves are poisonous if ingested in large quantities.

 

Cooking aubergines

The aubergine can be grilled, steamed, and baked. It is important for the aubergine to be cooked before eating as the peel and seeds can have a bitter taste. The bitterness will break down when the fruit is cooked. Raw aubergines contain 92% water, 6% carbs, 1% protein and basically no fat. The flesh of the aubergine has a spongy consistency and not a lot of flavour. However, the flesh has the ability to absorb fat and flavour, making the aubergine perfect for cooking.

Fun facts

• Aubergines, tomatoes, potatoes, peppers, and chilli belong to the same family.
• The aubergine belongs to the nightshade family.
• Botanically, the aubergine is described as a berry.
• The wild form of aubergine has spikes.
• It is still possibly to see those spikes on older varieties.
• In 2018, China and India together were responsible for 87% of the world production of aubergines.
• Aubergines are produced worldwide, and India has genetically modified sorts for production.
• It is only industrial sorts that are GMO (*)

(*) GMO is the abbreviation for a “genetically modified organism”. It covers a row of plants, bacteria, and other organisms, whose genetical material (their genes) has been altered, either by having removed or added an extra gene, or by having changed an existing gene to advance a certain quality, for example the resistance to a disease.

Cultivating aubergines

From March, you can start to pre-germinate the aubergine seeds in the windowsill inside. The aubergine is cultivated similar to tomato plants; however, an aubergine seed is slower to germinate than a tomato seed. It can easily take up to three weeks before the plant will break through the soil. Aubergines have a greater need for heat than tomatoes and especially in the beginning as a young plant, aubergines need more care.

How to

• Fill up your seed tray with potting soil, that has been adapted for germinating seeds.
• Make the soil moist and make a small hole for the seed.
• The hole must not be deeper than three times the size of the seed.
• Sow the seeds separate or make sure there is generous space between them.
• Cover your seed tray with a plastic lid, plastic, or fibre cloth.
• Place the seed tray in an east or west turning window. The optimal temperature is 22°C.

The first seed leaves/cotyledons

• Remove the plastic lid. It is time for the fragile, small plants to get to know the real world.
• The small plants need as much sunlight as possible.

The first true leaves

• When the plants have gotten their first sets of true leaves, the seedlings should be transplanted.
• Transplanting the seedlings usually happens three to four weeks after sowing.
• When the plants are about four to five weeks old, they need fertilizer.

Aubergines in the greenhouse

• The aubergine can be placed in the greenhouse (in Denmark) from mid-May.
• The plants should be hardened off slowly over a weeks’ time.
• Young aubergine plants can’t withstand temperatures under 15°C.
• The aubergine does not thrive on open land in Denmark or places with similar climate.
• The Juliana Urban Greenhouses are optimal to cultivate aubergines. 
• The aubergine will ripen in the beginning of august, so a little later than the tomatoes.

 

Vermin

The aubergine, like any other plants, can be attacked by disease and vermin. Especially white flies and spider mites attack the aubergine. Our best advice is to check your plants for vermin regularly once a week.

All insects love dry conditions, so the solution is to create the opposite. That means you can fight spider mites and white flies with water! Take a spray bottle or water hose and sprinkle the underside of the leaves, where the spider mites and white flies usually sit. This makes it impossible for the vermin to thrive.

Tip

The pollination of the beautiful aubergine flower can sometimes be a little difficult. That can be helped by lightly brushing a soft brush around the flower a couple of times a week.