Redesigning Zone One

As a general rule I avoid writing posts about my plans- reporting results is much more juicy. This post is an exception since I am at a turning point- redesigning my zone 1 home garden. You could call it a vegetable garden, but it has always been used for so much more.

The space in question is ten meters away from the house, 60 m long and 20 m wide (a total area of 0.3 acres). It is the largest relatively flat space close to home in our farm of rolling hills. Originally it was dense kikuyu pasture, which I divided into six cells with chicken wire to house my geese at night. They removed the grass and concentrated a little fertility from their daily foraging. Around the borders I planted hedges of Tithonia as a windbreak/goat fodder/goose barrier. Beds were prepared running east-west by hoeing the topsoil from the paths onto the growing space. After clearing weeds with a hoe the beds were prepared by topdressing biochar and goat manure in a central strip, then direct sowed along the edges.

Weeds were controlled by hoeing several times through the growing season, mostly on the path and bed edges, then piled up to die. I used no mulching since I had no biomass ready to use, and refused to bring in truckloads of machine processed mulch. Overall the method worked well and for several years I created six cells that periodically returned to geese, to be prepared and sown twice a year in spring and autumn. Old vegetable cells with residual fertility and lower weed pressure were used to trial staple crops most seasons.

During 2021 I burned out a bit, so let the space go (though it continued to produce crops for nearly a year). The summer of 2022 turned extremely wet, so it was fortunate I hadn’t planted anything the prior spring. Our soil is a peculiar heavy cracking clay that holds a lot of water, supporting crops with zero irrigation for about six months without rain, but it turns to a bog with prolonged rain even on the top of the hill. The topsoil on the hilltop is fairly thin. One day I might create a smaller vegetable garden in a low lying area to use during prolonged droughts.

Over the years of growing in the space I discovered the southern boundary crosses over an old road base, and fertility generally declines in the south and west. The Tithonia hedges eventually became woody and annoying to cut back, with significant root competition, so I cut them down one final time and burnt or sprayed them out. I also discontinued my goose flock, so removed all the bird wire. Experimenting with organic structures like bamboo trellises has convinced me to banish structural metal from the space going forward.

The vetiver grass boundary has now matured, but turns out to make a perfect rat nest habitat if left uncut. It is a useful living weed barrier around the space, but I am now committed to cutting it all regularly (something which is vastly easier to do if it cut before it turns woody). I didn’t use mulching when I established the space because I didn’t have the biomass on hand, but that situation has now changed. I also now realise how excellent Canna is as a mulching material (I would rank it as more useful than vetiver) and plan to plant the western half of the space with Canna as part of my breeding project. I may put a lemongrass border between the canna and growing beds, if I think I have enough time to cut it regularly and need of the extra mulch.

Laying mulch in one place forever is still a luxury I cannot afford. I suspect most people who are mulch enthusiasts would feel the same way if they didn’t have diesel or coal powered machinery doing most of the work for them. Even with half the space planted in Canna and a mature vetiver edge I would not have enough biomass to permanently mulch the remaining half of the space (I only need about half of it under crops at any one time). Instead I plan to leverage the limited mulch supply more effectively using a technique called stale seed bedding.

The biggest problem with weeds is during the early phase of establishing the crop. Under the worst scenarios a carpet of weed seedlings will germinate around your crops and smother them if you don’t go through the fiddly work of separating them by hand. Permanent deep mulching kind of solves this, but usually it only works if you transplant seedlings into holes in the mulch (which demands a whole lot extra work and resources and gives substandard results due to root disturbance).

Stale seed bedding seeks to reduce the weed seed bank in the soil before you plant your crops. Often this is achieved by clearing the space, waiting for weeds to germinate, then smothering them with a sheet of heavy plastic while they are small. I wanted to get away from relying on plastic, so wondered if focused use of mulch could achieve the same result. As such I have created a system of mulch banks, rolling across the weedy landscape like waves, with gaps of bare soil between them to tempt the weeds into germinating, only to die when the next wave smothers them. Moving the rows forward with the hoe is pretty quick and light work, and the mulch can be piled deep enough to smother even perennial weeds like dock. Most importantly it allows a limited amount of mulch to have a much larger impact than it would sitting in one place until it rots. I suspect regularly lifting the mulch will slow down its decomposition (and make it less attractive for vermin).

The proposed shape and proportions of the growing beds now works a lot better since materials don’t need to be transported as far. The Canna beds run parallel to the whole space, providing mulch. The goat pens are also positioned to provide manure and stripped branches without excess movement. When you move all your material by hand such things quickly become important.

This approach should allow me to transition from the previous batch approach to bed preparation (where I had to rush to prepare a whole cell in time for spring or autumn) to a continuous approach (where a new bed is prepared, and sowed every few weeks provided soil moisture is sufficient). The continuous approach works better now I have given up large scale variety trials to focus on the smaller range of vegetables that are proven performers under my conditions, and should allow me to produce a more steady supply for the kitchen. Currently beds are being prepared starting in the north east corner, moving to the south, but ideally I will reverse the direction from south to north so that newly germinating crops are not shaded by more established crops to the north (mostly an issue in winter when the sun dips). Soon I will burn my Tithonia branch piles on the southern end and start working northwards. The best looking Canna hybrids will be selected from the mass planting further from home, one clone per bed so I can evaluate starch content later on.

The final piece of the design is the northwest corner, where soil fertility is a bit lower but the proximity to the house puts the space at a premium for convenience. This is where I plan to move all my herbs and perennial vegetables, though I have decided to give up on the Mediterranean herbs (rosemary, oregano, thyme) that regularly collapse during our wet summers and struggle on our low calcium clay. I will do a follow up post on the herbs and perennials that make sense under my conditions, sometime in the future, as well as a report on how the new design worked in practice.

Alternating rows of vetiver mulch and bare soil for stale seed bedding

An aerial view of my zone one space. Green border shows vetiver edge.