Under-planting

“Under-planting” is the term used in gardening to describe the concept of growing a small plant underneath a bigger one, in order to maximise the yield from the available space. Since my garden is small, this is a technique I frequently use.

Here are some examples:

This is Landcress underneath Purple Sprouting Broccoli.

And this is Endives underneath Brussels Sprouts.

Here are some tips, based on my experience with the technique:

• The bigger plants may overshadow the smaller ones and prevent them getting enough light, so you have to aim off for this. You will notice that I have removed many of the lower leaves of my Brussels Sprouts, which helps the Endives to get their share of light. Also, for the same reason, I put the smaller plants around the edges of the bed rather than directly underneath the big ones.

• Plants that tolerate some shade are good as the “underneath” ones – e.g. Parsley, Celery Leaf, Endives, Spinach, but definitely not Radishes. Their small size makes them sound ideal, but Radishes will bolt if they don’t get sufficient light.
• Choose plants that like roughly the same watering regime, since you may be unable to water one without watering the other. Furthermore, excessively thirsty plants are not good ones to use for under-planting, because they may deprive the “main” plants of water.
• Consider whether sowing / planting the smaller plants can be done without disturbing the roots of the bigger ones. Sow / plant at the same time, if you can – e.g. sow some salads at the same time as planting-out some brassicas seedlings.
• Using the under-planting technique doesn’t give much opportunity for weeding. But then again the additional ground cover it contributes often prevents weeds from taking over where they might otherwise do so. For example, Squashes or Pumpkins grown below Sweet Corn.
• If you are going to cover your plants with nets or mesh, think about the practicalities: I planted Landcress and Lamb’s Lettuce (Mache) underneath my PSB, which was netted, but this meant that any time I wanted to harvest the salads I had to pfaff about partially removing and then replacing the nets. It might have been better to plant something that only needed harvesting once, as opposed to repeatedly.