What is the best kept secret in container gardening? The experts know how to promote faster, more vigorous growth, and significantly reduce the chance of pests and diseases... ssssh... it all comes down to healthy soil.
3. How can we promote health and extend soil life?
The following points can be used as a basic guideline to establish and maintain good soil health.
a) Start with good Soil Structure
Start with a potting mix that uses bark fines, and be sure that the mix is loose, never overly wet or compacted. Potting mixes containing bark fines will generally break-down slower than softer peat based mixes.
Consider adding Perlite to your potting mix to improve structure. Perlite is a super light-weight, expanded form of inert volcanic glass which will not break-down or compress in the soil. Perlite is readily available and simple to use, although take care not to breathe-in the dust. Mix approximately 1 part Perlite to 10 parts soil. Perlite reduces the density of your soil mix, preventing general collapse, and it creates pockets for water and air in the soil whilst allowing drainage.
b) Feed regularly
The best practice is to regularly apply natural Liquid fertilizers - like worm tea, seaweed extracts, or organic plant food blends with trace elements.
WORM ALERT: If you haven't already considered starting a worm farm, now is the perfect time. Kitchen waste, scraps and garden waste are effortlessly recycled into "liquid gold" plant food, and the impact on plant health and growth is remarkable. Do yourself a favour!
When re-potting or recovering soil between crops it can also be a good idea to add organic matter like worm castings, or compost to the soil.
The use of a good quality, organic, slow-release fertilizer can also be used when rebuilding soil between crops, particularly after intensive, nutrient hungry crops like tomatoes, eggplants, peppers, and leafy greens.
c) Provide cover
Adding pea straw and other plant based mulches as a soil cover is a great practice. This will reduce evaporation, lock-in moisture, protect the topsoil from temperature extremes, UV light, and create the perfect environment for beneficial bacteria and other organisms. Mulch will break-down over time and can be turned into the topsoil between vegetable crops to further decompose and improve soil structure.
d) Change it up
Crop rotation... it's simple... Don't' plant the same crop in the same soil year after year.
Plants absorb different quantities of soil nutrients, and repeated plantings will quickly deplete the soil. Crop rotation therefore allows for a more balanced soil fertility and microbial balance. Furthermore it can prevent a build up of pathogens in the soil which can infect and continue to re-infect particular families of plants.
Want to keep reading? Here's what's up next...
4. How often should container soil be changed?