Good soil holds moisture
Watering is usually a problem when you grow in containers, as they just can’t hold the same amount of water as an in-ground bed, and also because containers are usually planted quite densely.
They also tend to dry out quite quickly, especially porous terra-cotta containers, and in a hot climate the soil will get quite hot and dry.
The ”soil”, which is often not more than low-quality peat, often becomes kind of waterproof, whatever you do you can’t get it to absorb moisture.
One of the great things with bokashi is that it adds a huge amount of organic material to whatever soil substrate you’re using: peat, clay, sand. This improves it’s ability to retain moisture for longer. So that when you water your garden it will actually stay watered. Yes!
So your containers will be easily to water and keep moist. That’s good.
But there’s another issue. Containers always have drainage holes, and any water that’s not retained immediately will drain out.
Some have water reservoirs built in, a kind of zone at the bottom of the container that holds excess water under a grid and allows the plant roots to suck it up later, or alternatively the soil itself to suck it up through osmosis.
These types of containers (and you can make them yourself) are great because they cut down the need for watering. But there’s another valuable thing, and that’s to do with nutrients.
It’s such a pity to have a lot of bokashi in your soil, to have a soil really full of nutrients, and then — because it’s raining a lot, or the containers are being watered a lot — to watch a lot of those nutrients wash away through the drainage holes in the pots.
Often to no avail because there is no soil underneath to absorb them, so the nutrients are just lost in the gravel or on the asphalt.
I tend to grow a lot of stuff in big plastic tubs that I’ve adapted to have a decent- size water reservoir. (You can have long discussions about the merits and otherwise of growing vegetables in plastic that may or may not be food quality, but lets leave those for another day).
These big black tubs, they come from the cement business, are usually 60 to 100 liters. I use them in and around my greenhouse, on my deck for growing snail-free salad and herbs, and around the house to just brighten up some ugly corners with flowers.
These tubs have no holes, obviously, but rather than drilling drainage holes in the bottom, I just drill one biggish hole on the side of each tub some 10 cm up on the side. I then fill the tub with drainage material (clay ”leca” balls in my case) up to this level.
This will form the water reservoir; any runoff from the soil will be stored in this area, amongst the drainage material, and only if it reaches the height of the hole will it run out.
That way I’m protected during rainy periods, my plants won’t drown, but in any normal circumstances they will always have access to nutrient- rich water from the reservoir.
The rest of these tubs I just fill with soil and bokashi as described above. I tend not to empty them, ever, but each spring I dig down some fresh bokashi into the existing soil to freshen them up.
This method is so extremely simple, using bokashi to fill buckets, tubs and planters for a container garden, but it is incredibly effective.
And rewarding, because the flowers and herbs you grow on your terrace and balcony, or in your urban garden, will be so much healthier and stronger than you’re used to.
And they may even have worms!
/Jenny Harlen, Bokashi World