Written by Spirekassen 17 Oct 2022 11:09

Fertiliser and irrigation for winter cultivation


There is no doubt that it is autumn in the greenhouse. You can use your greenhouse to save money on the food budget – even when it is autumn. It is October, but you can continue to cultivate vegetables all winter long in the greenhouse. Although, you will have to cultivate other plants than those you would cultivate in summer. Also, other forms for irrigation techniques and fertilisation techniques will be needed.

The first thing you may notice when cultivating during winter, is how slowly they will grow – and even slower when you reach the end of the year. It might be tempting to start fertilizing the plants to help them and to kick-start their growth, but that is not the case. 

To make a plant grow, you simply need to make sure that a couple of basic needs are met. Just like the human existence depends on a few basic needs such as food and water. Plants are just like that. The basic needs for growth must be present and in the right amounts to have growth that is ideal and healthy.



Few but important elements

Light, water CO2, oxygen heat and nutrients

Throughout the winter there is a lack of light and heat. However, do not help the winter cultivation along by providing additional heat or use grow lights. Let nature provide the free sunlight and warmth in the greenhouse on those wonderful winter days.


Liebig’s law of the minimum

Knowing this law when cultivating is important. The law of the minimum helps you understand growth, and you will know what to do and what not to do during your winter cultivation.

Plant growth is limited if one of the essential nutrients is deficient – even when all other essential nutrients are abundant.

Essential nutrients can for instance be light, water, CO2, oxygen, heat and nutrients. All winter cultivated plants will eventually lack light and heat during winter. In other words, adding fertiliser and water will not contribute to their growth. The plants will not be able to effectively use the nutrients, due to low temperatures in the greenhouse, and the water in the leaves will not evaporate as much as they did in the summer months. Therefore, winter cultivated plants need less water. The plants will grow on days with mild temperatures and sunlight – but they will be growing slowly. 



Plants for winter cultivation

  • Lettuce (short-day varieties)
  • Broad beans
  • Chicory
  • Napa cabbage
  • Cabbage
  • Peas


Tips on winter cultivation

  • Know the law of the minimum
  • Avoid using fertiliser in the greenhouse during autumn and winter
  • Irrigate once a week
  • Reuse the soil from your summer cultivation