This post is the second part of Thought Exercises 1. To read part one click here.
In the last post I went thought the reasons for structuring a vegetable garden as tiered boxes, and the general structure itself. I take the thread back up again by detailing just what I meant by "optional extras" for the B boxes. To refresh your memory, here is a re-print of the schematic.
|Fig. 1 Bird's-eye schematic|
The additional options for boxes B that I referred to are that the inside walls could easily be designed to be put in or lifted out in stages. Why would this be useful? For greater yield of potatoes and carrots, mostly. Potatoes grow very well sideways, as everyone who has ever seen a potato field knows, but they also grow very well upwards. As in, place a potato at the bottom of a box and cover with soil as normal. The leaves and stalks will grow up and when they reach over the top, make the box taller and fill in more soil around the stalks. Keep doing this until you have reached maximum stability or plant maturity. When the plant has died back sufficiently, harvesting is a matter of pulling off the boards again and sifting through the soil. This method has been shown to yield as much as 100lb in 4 square feet, some examples of other people's explanations with diagrams can be found here and here.
The question of crop rotation always comes up and particularly with nightshades (includes potatoes, tomatoes, peppers and eggplants), but with the 'upward box' method, you can relatively easily change out the soil after a season if you do not have the luxury of being able to plant your potatoes elsewhere. Place a tarpaulin in front of the box, remove all of the boards, shovel the soil onto the tarp (harvesting can of course be done at the same time) and bring the tarp of soil to your previously chosen location. The potato box can be reset to the initial height and refilled with e.g. leaves, compost, soil, or at this particular location seaweed, finishing with a thick layer of mulch. Done in the Autumn/Fall, this will allow your bed to rest and the organic matter to finish breaking down so that in the Spring you can start the process again easily.
Okay potatoes, but what was that about carrots? Did you kow that carrots grow towards water? With a box with a removable side, you can place in a non-permanent bottom irrigation system consisting of two pipes, a 90-degree bend, a cap and a funnel. Again utilising the tarp method of soil movement, if you decide that the irrigation system is better suited elsewhere, you can remove all of the boards, lift out the pipes and replace the soil without resorting to back-breaking digging. For illustration, see Fig. 2. These types of beds are often referred to as wicking beds.
|Fig. 2 Side schematic of bottom irrigation system|
The purpose of this is to deliver water where you, the grower wants it, UNDER the carrots. Carrots that can get all the water they want from the surface, don't seem to stretch down very far as I learnt from my own experiences. But with this irrigation system, you can pour your water/compost tea etc. down the top pipe and it runs along the bottom pipe, leaking out into the soil through the drilled holes. Be sure to replace the cap (cos all kinds of flying things looove small undisturbed pools of water to breed in and no one likes mosquitoes...) and you are done!
In previous posts we have written about the importance of planting specific groups of plants or Plant Guilds together to combat pests and to enable more vigorous growth. Companion Planting goes for the same principle, but the recipe of 'crop, feeder, protector' need not be so strictly applied. But for the example of the carrot beds, I would plant in calendula to repel root nematodes as well as the tomato hornbeetle and some leaf lettuce and onions, because you cant have enough onions. HOWEVER, unfortunately calendula apparently tends to attract slugs and spider mites (I have not seen any evidence to back this up myself, but it seems some others have). Beer traps, salt trails, and some bird perches should alleviate the problem without recourse to harsh chemicals. Again, in order to create your own Companion Planting list click here for the comprehensive list that I regularly use.
For the potato boxes, I would be very interested in trying to grow horseardishes and shallot onions in with the potatoes and seeing how they respond to the climbing soil level. Would they also grow upwards, resulting in more elongated bulbs? Or would they simply be smothered? If anyone out there has any experience in this or is willing to give it a try, please let us know and we'll make sure you get your credit.
So here ends Thought Exercise 1, I'm sure there will be more. I want to work through how to develop a free-standing, low-maintenance herb tower, so you may see that at some point too. Until then if you have a comment or question feel free to use the comment box and, as always, have a great day!