Healthy Windowbox crops... Plant Nutrition

Give your plants the best start

Fill your windowbox with a good, fibrous compost, preferably with some loam or clay in it to retain moisture and slow down the leaching of nutrients. You can also mix in homemade compost, which can be easier to make than you might think and needn’t be smelly at all. My secret to success is to bury bits of seaweed collected off the beach (OK if you live near the sea like me!), which will act as a slow-release fertiliser as it breaks down. Do make sure you bury it though as it can be a bit stinky !


As the plants grow and especially during the Summer months, the windowbox will need feeding as the nutrients in the soil will soon get depleted. The easiest way of doing this is to buy and scatter organic granules of seaweed or chicken poo over the soil surface, although be careful not to overdo it. These will be gradually washed into the soil and slowly release their goodness to the plant roots.


Another thing you can do, in addition to the above, is to you use semi-rotted garden compost to mulch the surface of your windowbox – This will act as a slow release fertiliser as it breaks down and also has the added bonus of reducing water loss from the soil surface and restricting weed growth.


Mulching is best done in early spring, when plants are just coming back into growth - mulch around evergreen plants and shrubs whilst putting mulch directly on top of perennial plants that die back over winter (such as the Mint in the second picture)

Make your own feed

If you've made a compost bin like mine then you'll be able to siphon off a liquid feed. Alternatively, if you've got access to nettles or comfrey you can use the leaves to make a very nutritious feed for your windowbox:
1) Simply pick your leaves and squash them into a plastic soft drink bottle with the bottom cut off.
2) Up-end it on to the top of a second bottle and tape together with duct tape or other waterproof tape.
3) Place a stone on top of the leaves and leave for at least three weeks for the black liquid to ooze through into the bottom bottle.
4) For larger quantities you can rig up a section of drainpipe in a similar fashion.

Dilute your liquid feed in a 1:10 ratio with water and drench over your windowbox.

Make sure you rinse any crops well before eating them!



Check on the individual growing requirements of your chosen plants before feeding or mulching to make sure you provide them with the right levels of nutrition!