High Production Container Gardening in a Small Space Using Sub-Irrigation Planters (SIPs)

We live in an older house on a larger city lot, with a shady back yard and a small sunny front yard, so we struggle with limited space for a vegetable garden, like many people do. To work around these factors, we use a sub irrigation method of gardening that allows us to do high production container gardening on our asphalt driveway. 

We have found this approach to be very flexible and accommodates our lifestyle and gardening goals.



Sub-Irrigation Planter Box

Using a Do-It-Yourself sub-irrigation approach, we make our own closed system planters. These are large plastic storage totes that we modify to add a raised floor with a 5 gallon water reservoir in the bottom and an overflow vent.

The plants water themselves as needed though water wicking. This approach makes it easy to water your garden, use water efficiently and not have to worry about under or overwatering.

I'll make a page that shows how to make these planters in a future post.




Vegetable boxes kept under cover in a warm place


Once the planters are up and going, they are very low maintenance and completely portable, so they can be moved in and out of a greenhouse for extended growing. 


This is also a great way to start a garden in a limited space or in cases when you are unsure about where the final garden location will be. 





We start our boxes in a greenhouse as early as February.  The boxes are kept in a group in a warm area until late spring.
 

This set of boxes contain lettuce and peas. We started them early and set them out under a plastic cover to create cold frames. This helps get a jump on the growing season.

SIPs in the driveway

We move the boxes out into the driveway once it is warmer. In this case, we started out by tucking our SIP boxes against the retaining wall at the side of our driveway, where it is very warm and sunny.




Tomatoes grown over a arbor gate

We grow all kinds of vegetables in these systems, including corn - which gets quite big and loves to suck up water.




Tomatoes also get big and consume alot of water, so we grow two plants in each box to control the crowding problem that occurs over the summer.  Very large tomatoes are trained to an arbor gate to support the weight of the plants, improve airflow and make it easy to harvest as they ripen. 







We bring in a steady flow of tomatoes (and everything else) from late summer until frost, when we clear the vines and have alot of green tomatoes.








Watermelon Trellis

Cucumbers, watermelon and peas are grown vertically on trellises.  We like to grow Tiger Baby watermelons because they stay small and we can suspend/support them in little slings from the trellis.


 

Assorted Peppers

We reuse the soil each year, but practice 'crop rotation' in a way that rejuvenates soil (last year corn, this year beans, etc).  Except for the asparagus, it stays put permanently. 



We augment the soil each spring with compost, lime with magnesium and a fertilizer.  We typically grow all the normal vegetables that you'd expect in a garden.






Apple Tree in a pot


We also use this approach for our fruit trees, though we actually use a combination of three techniques - bonsai, espalier and sub irrigation.

The fruit trees are started in 24" pots and grown for 2 - 3 years until they are ready to go into the larger sub irrigation planters (it is easier to move the trees around and find where they do best in the smaller planters). These fruit trees are semi-dwarf and root trimmed every third year.

Tree with Espalier

After they have grown branches that are long enough to train - generally on their third year - we build a bamboo "table espalier" about 5' above the tree and train the branches to the trellis.


The overhead trellis achieves many things at the same time - it supports the weight of the fruit and protects the branches from breakage, it provides good air circulation which reduces disease and fungus, it makes the fruit easy to harvest and the tree is easy to prune and check for bugs or other health issues.



We grow quince, apples, pears, cherry, peach, and nectarine this way.  We also grow hazelnuts in containers using the bonsai method.





There is a specific approach to fertilizer when growing fruit trees in a container/bonsai approach.  You use a different NPK ratio than normal and you add it a lot more frequently.  I'll go into that in more detail in a future post.