Another fruit vegetable that I really like is eggplants. Some people walking by approach me from time to time and ask me about the eggplants. The number of fruits and, above all, the high quality makes some people stare, especially when I mention that everything is produced completely without pesticides. I was delighted with the praise and would like to share my knowledge here so that you can also grow them successfully in your home garden. But should you grow eggplants at all?
People often talk about fertilizing, watering, planting distances, etc. when it comes to growing vegetables, but there is hardly any information on cultivation duration and realistic yields. Therefore, in this article I would like to shed light on the “other side” of cultivation and take a more critical stance.
Die Herausforderungen
First of all, it is important to understand that the entire cultivation period for eggplants very long compared to melons. It can take a good 20 weeks from sowing to harvest. To make matters worse, eggplants are very sensitive to the cold as young plants and only germinate at a constant 20-25 °C. Direct sowing is therefore impossible. Direct sowing is therefore unthinkable in Switzerland and “natural seasonal production” is out of the question, as the plant would have no chance of survival without pre-cultivation.
If you don’t have an efficient way of growing eggplants from February onwards, you can fall back on seedlings. As I attach great importance to resource-conserving production, I clearly prefer plants that also thrive as direct seedlings. In my opinion, you should always be critical when it comes to growing tropical fruits in Switzerland. Various studies show that imports are often more environmentally friendly as long as they come from careful cultivation (e.g peppers, tomatoes).
Sobald es die Temperaturen zulassen, sollten die Auberginen schnellstmöglich gepflanzt werden, da nach der Pflanzung erneut rund 10 Wochen vergehen, bis die ersten Früchte geerntet werden können. Je nach Sorte dauert die Ernte dann 8 Wochen an, bis die Pflanzen eine natürliche Stagnation aufweisen und weniger/keine Blüten mehr ausbilden. Auberginen kommen aus dem tropischen Indien und sind in ihrer Ursprungsregion mehrjährig! Daher die Stagnation der Fruchtbildung, die erst wieder nach einigen Wochen bis Monaten aussetzt. Im Profianbau werden daher mehrere Sätze an Auberginen gepflanzt, um die Anbausaison zu verlängern. Dies ist aber nur möglich mit intensivem Heizen, welches aus energietechnischen Gründen oftmals keinen umweltschonenden Anbau zulässt. Wer Auberginen im Hausgarten, bestenfalls unter Glas oder im Folientunnel anpflanzt, erntet daher vorwiegend im Juni und Juli. Viel früher kann ohne Heizsysteme nicht geerntet werden und ab August werden die Nächte wieder kälter, respektiv steigt die Luftfeuchtigkeit oftmals an, so dass ein Faulen der Früchte ohne Spritzmittel nicht zu verhindern ist. Wir stellen also fest, dass der Anbau von Auberginen in der Schweiz ohne Heizsysteme stark limitiert ist und die Ernte auf die Sommermonate begrenzt ist.
As soon as temperatures allow, the eggplants should be planted as quickly as possible, as it takes another 10 weeks after planting before the first fruits can be harvested. Depending on the variety, the harvest then continues for 8 weeks until the plants naturally stagnate and produce fewer/no more flowers. Eggplants come from tropical India and are perennial in their region of origin! Hence the stagnation of fruit formation, which only starts again after a few weeks to months. Professional growers therefore plant several sets of eggplants to extend the growing season. However, this is only possible with intensive heating, which often does not allow environmentally friendly cultivation for energy-related reasons. Those who grow eggplants in the home garden, at best under glass or in a foil tunnel, therefore mainly harvest in June and July. It is not possible to harvest much earlier without heating systems. In addition, from August onwards the nights get colder again and the humidity often rises, so that rotting of the fruit cannot be prevented without intensive sprays or heating. We can therefore see that the cultivation of eggplants in Switzerland without artificial heating systems is severely limited and the harvest is restricted to the summer months.
However, the uncertain success is not only due to low temperatures, a second major sticking point in the cultivation of eggplants are pests and diseases. As a nightshade plant, potato beetles truly love eggplant plants, and if there is a potato field in the immediate vicinity, they are practically guaranteed to fly in. Other important pests are aphids and spider mites. Aphids are particularly prevalent on young plants and can quickly lead to total failure. By growing in mixed crops, I have been able to drastically reduce the infestation of aphids, but I am still not able to fully control them. Spider mites are a problem in the protected cultivation of eggplants, especially on older plants, and occur in hot, dry climates. In principle, spider mites can be controlled very well by increasing the humidity. However, this is a delicate matter, as it can lead to the eggplants being infested with gray rot. It is therefore extremely important to ensure that there is always a medium level of humidity in the air and soil.
How many fruits does one eggplant have?
If the summer is just right for the eggplant plants, the microclimate is optimal and the pest pressure is low, the harvest can be expected to last around 2 months. According to practical yield estimates, 3.3 to 5.3 kg per plant can be expected in good conditions in the polytunnel. I do not consider these yields to be realistic for the home garden, and I also assume that these are grafted F1 plants. In my experience, yields in an optimal growing season are around 2.4 kg/plant for conventional varieties, but can also be significantly lower.
Should I/you grow eggplant plants?
Buying seedlings is almost always associated with a high CO2 footprint compared to direct sowing. If you have the opportunity to create optimal growing conditions for the plants, or can even grow seedlings yourself indoors, you can certainly enjoy the high quality of your own fruit. However, if you don’t have such facilities and are not experienced in growing fruiting vegetables, you can certainly make better use of the space in your garden or on your balcony in other ways. Personally, I am skeptical about growing vegetables that have been “artificially” cultivated for a long time and cannot be grown directly in tunnels without additional heat. Moreover it’s not possible to produce economic yields of eggplants without the use of energy-intensive heating systems in Switzerland. As I have no environmentally friendly way of artificially extending the growing season, my cultivation is as well limited to the summer. That’s why I’ve been avoiding growing eggplants since 2022 for commercial cultivation and stuck to a few plants for myself.