The land constraint in Ruaraka

Ruaraka Sub-County, and Kariobangi North in particular, is dense. Most households simply do not have horizontal space to expand a garden even if they wanted to. Vertical farming is our answer to that constraint: instead of expanding outward, growing space expands upward.

Structures our members actually build

The simplest vertical structure we teach is a tiered planter built from stacked used tyres or timber offcuts, filled with soil and arranged so each tier gets adequate light without shading the one below it. This is often the first vertical structure a member builds, since materials are cheap or free and the technique is close enough to standard bed gardening to feel familiar.

A step up from tiered planters is a wall-mounted pocket system, using repurposed fabric or plastic pockets fixed to a fence or wall, ideal for shallow-rooted crops like lettuce, spinach, and herbs. Sack gardening, covered in a separate training, is itself a form of vertical farming, since a single sack effectively stacks growing space vertically within a small footprint.

Light, water, and structural considerations

The main technical challenge with any vertical structure is uneven light and water distribution — upper tiers dry out faster and can shade lower ones. We teach members to orient tiered structures so the tallest side faces away from the sun's path, and to build in a drip or gravity-fed watering system similar to the one used in sack gardens, so water reaches every tier without manual watering can by can.

What members are growing this way

Vertical structures in Ruaraka are mostly used for fast-growing, shallow-rooted crops — kale, spinach, coriander, and similar herbs — rather than root vegetables or anything needing significant depth. For households with genuinely minimal ground space, a well-built vertical structure can realistically multiply usable growing area several times over compared with flat ground alone.

Materials and cost for a basic tiered structure

Members often ask what a first vertical structure actually costs to build, and the honest answer is that it can be very close to free for a household with access to used tyres or timber offcuts, which are the two most common materials for a basic tiered planter. The main cost, where one exists at all, is usually soil and manure to fill the structure rather than the structure's frame itself, which is why we generally introduce vertical farming to members who already have some sack or bed gardening experience and an existing relationship with our group input buying program for soil amendments.

For members without easy access to free tyres or timber, a simplified version using stacked, repurposed plastic containers with drainage holes cut into them can achieve much of the same vertical effect at a similarly low cost, though this version tends to be less structurally stable in heavy rain and needs more careful anchoring.

Combining vertical structures with rainwater harvesting

Members with both a vertical structure and a rainwater storage system have found that positioning the two together — storage tank feeding directly into the vertical structure's drip system — solves both the watering-difficulty and water-source problems in one combined setup, rather than solving them separately. This kind of combined design takes more planning at the outset than building each system independently, but it saves considerable ongoing effort in watering a structure that would otherwise need manual attention tier by tier.

We now encourage members planning a first vertical structure to think about water source at the same time as structure design, rather than treating watering as an afterthought to be solved once the structure itself is already built.

The right vertical structure for a given household depends almost entirely on what materials are already available and how much time can be spent building and maintaining a watering system for it. We generally advise new members to start with the simplest tiered planter first, get comfortable managing light and water at that scale, and only move to a more elaborate wall-mounted system once the basic principles — even light, even water — are second nature. As more members build vertical structures, we are also collecting informal feedback on which designs hold up best over multiple seasons versus which need more frequent repair, information we plan to fold back into future training sessions so newer members benefit from the accumulated experience of those who built the earliest structures.

Key takeaways

  • Vertical structures multiply growing area upward when horizontal space is unavailable.
  • Tiered planters from stacked tyres or timber are the simplest starting structure.
  • Wall-mounted pocket systems suit shallow-rooted crops like lettuce and herbs.
  • Orient structures so the tallest side faces away from the sun to avoid shading lower tiers.

Frequently asked questions

What crops work best in a vertical structure?
Fast-growing, shallow-rooted crops — kale, spinach, coriander, and similar herbs — rather than root vegetables that need depth.

Is sack gardening a form of vertical farming?
Yes — a single sack effectively stacks growing space vertically within a small footprint, which is why we treat it as part of the same family of techniques.

How stable are tyre-stack planters in heavy rain?
Reasonably stable if built low and anchored, though very tall stacks should be secured against a wall or fence for safety.