vegetable patch management
pots
ground pots
Ground pots are used to concentrate water directly to specific vegetables and/or to protect them from invasive tree roots.  They are also a good way of using up all those old black pots gardeners inevitably have lying around.

description of a ground pot
Illustration of a ground pot.
Ground pots maximise water uptake and protect vegetables from invasive roots.
A Ground Pot is a plastic pot that has had it's bottom removed.  The top of the pot remains unchanged but the bottom has a crude  serrated edge on it to make it easier to drive the pot into the ground.

uses of ground pots
There are three key uses for ground pots.
  1. Keep invasive tree roots from stealing water and nutrients from vegetables.
     
  2. Conserve water when water supplies are limited.
     
  3. Concentrate lots of water to vegetables that need a lot of water such as celery and pak choi.

ground pot sizes
Photo of a ground pot in the ground.
290 mm (12") ground pot in the ground with young radicchio plants in it.


Photo of two ground pots
Two ground pots showing the serrated edges at their bottoms.
To be effective ground pots have to be big enough to hold sufficient water for the plant's needs for a reasonable period of time. 

The ideal pot sizes are 290 mm (12") and above.   250 mm (10") pots are acceptable for smaller vegetables but anything below this size can't hold enough water.

ground pot depths
If you cut off the bottom of a 250 mm pot you will get a depth of 200 mm (8").  A 290 mm pot will have a depth of 250 mm .

250 mm is deep enough, any deeper and it becomes too much work to dig them into the ground.  So if you are using pots larger than 290 mm cut 250 mm from the top of the pot and not from the base of the pot itself, which with larger pots will be deeper than 250 mm.

Making a ground pot
Making a ground pot is simple.  With a stanley knife cut the bottom off the pot, then with a scissors or secateurs cut V shape indents out of the bottom edge of the pot at  regular intervals to create a sawtooth effect.

For making lots of these pots I have found it quicker to use a 100 mm grinder with a thin grinding wheel on it.

using a ground pot
Ground pots work best in soft friable soil, if the ground is hard then they are much harder to dig in.
  1. With a fork loosen up the soil where you want to place the ground pot.  If your soil is very soft then you can skip this stage.
     
  2. Dig a hole to about 1/2 the depth of the ground pot.  I use a Ho Mi Asian cultivator but any old spade will do.
     
  3. Push the pot into the hole at the same time rotating it with your hands.  The serrated edge at the bottom will cut it's way into the soil as it rotates.  Leave about 50 mm (2 ") of the top above the soil as this will act as a barrier that you can run mulch up against.
     
  4. Fill the rest of the pot up with soil you have removed, plus compost, manure fertiliser etc..  The pot is now ready to be planted out.
CONCLUSION
Ground pots conserve water and protect your vegetables from invasive roots, just like wicking beds, however they are much cheaper to make and more versatile, making them a good alternative to wicking beds if you are on a tight budget.  They are also a good way of recycling waste pots.