How to make a no-dig kitchen garden
I spent the last few days building a new kitchen garden, and I'm really happy with how it's turned out. If you've visited my farm it'll all sound a bit bonkers - I already have a 450sqm vegie patch in a different part of the property - but you'll have to trust me on this one, there's method in my madness. My thinking went something like this: I wanted a garden closer to the house, and I wanted it to be productive, quickly.
The site I chose is barely 10m from the kitchen, adjacent to one of our perennial edible borders, close to a tap and flooded with all day sun. Since we stopped growing vegie commercially, there was no need for a massive patch. A little one will provide all of our salad greens and small veg with capacity to spare, while things that need space, like corn, small scale grains, pulses, and pumpkins, will go down in the big patch.
Then there's our nutrient deficient soil. This has been a major challenge, and the solution I've come up with for improving the fertility of my big vegie patch involves time and and repeated green manure crops to add lashings of organic matter. To grow veg for the household, I needed a patch with something like instant fertility, and the best way to do that was to make some new no-dig beds using imported materials.
Here are the details, and some suggestions for how you can go about building a garden like this at your place.
- Most of the site for the garden was previously rough lawn. To clear the grass and (ahem) weeds, I sprayed it with (swear word) glyphosate. Yes, you heard right. I'm an enthusiastic organic gardener, but I made a deal with the devil and sprayed with one of the organic industry's most loathed compounds. I'm not losing any sleep over the decision. For the overwhelmingly majority of my gardening experience, probably 99 percent over almost 20 years, I've used no toxic chemicals whatsoever. But there are the odd occasions when considered pragmatism is the order of the day. I needed to get this garden built within a quick timeframe, which meant that slower, organic gras clearing techniques such as sheet mulching and solarising weren't really feasible. I figured that a single, thorough spray with glyphosate would kill the kikuyu in one fell swoop and do minimal, only short term damage to the soil. I don't plan to maintenance spray with glyphosate, so there will be no lasting issues. It's a compromise, but sometimes you've gotta do what you've gotta do to get the job done.
- With the turf dead or dying, it was time to make some no-dig vegetable beds. Rather than make these from my existing site soil, which is very free draining and heavily leached of nutrients, I decided to import a gutsier soil/compost mix. This contained 50 percent red volcanic loam (with a higher clay content than my site soil), and 50 percent spent mushroom compost, premixed by the landscape supplies yard. Both ingredients will help hold moisture and nutrients (via electrical charges, increased surface area and other means) much better than my site soil can. Because mushroom compost is slightly alkaline, it should balance out the slightly acidic red soil to achieve a pH close to neutral - ideal for growing a wide range of vegies.
- Two cubic metres of soil was enough to make nearly all the beds, which were shaped to a height of about 150-200mm and a width of roughly 800mm. To the soil/compost mix I will add rock minerals at the rate of about two handfuls per square metre, along with blood and bone and pelletised chook manure at the same rate. This should cover most of my fertility bases. The total cost for the soil, compost and a 25kg bag of rock minerals, including delivery, was $182.
- I made the beds directly on the existing soil without doing any preparation. This was a considered decision. My soil is soft, drains easily and doesn't ever become really compacted. The organic richness of the bed mix I used will attract earthworms and microbes, which will gradually improve the fertility of the underlying layer of site soil. I also plan to loosen this layer with a digging fork, just to help break any crust that might be a barrier to plant roots and moisture. If your soil compacts easily, I'd recommend doing some prep work prior to making the beds. Consider deep ripping, applying gypsum, broadforking - whatever means necessary to break up the hardpan.
- Between the beds, I laid paths of wood chip. I got this for free from the council when they cleaned up a eucalypt tree that fell across our lane during a windy blast a few weeks ago. This hasn't been aged, but because it isn't being used to mulch the beds, I'm happy to just let it age in situ. Long term, these woodchip paths will gradually decompose and can either be scraped onto beds as mulch or simply topped up with fresh chip as necessary. I used just under two cubic metres of chips for the paths in the garden, which would cost around $100 if I had to buy them. Alternatives to woodchips include things like sawdust, bark, straw, and sugarcane, but none of these last as long as chips.
- I designed the beds to be curved, partly as a means of intercepting surface water runoff without causing it to pool, and partly because I like curves. My last garden was fairly geometric, with lots of straight lines. This one is curvier than a Rubens nude. It feels softer and more organic, even sensuous. The levels on this part of the block are all over the place so I ditched my original plan to put the the beds on contour, and just eyeballed them roughly across the main slope instead.
- I'm confident that I'll be able to plant straight into the beds. The mushroom compost will probably continue to decompose a bit, but there'll be enough fertility to feed some cool season vegies through their slow and steady winter growing season. I'll top the beds with further compost and other goodies in spring, ahead of the much more demanding summer growing season.
There you have it, a quick and rough guide to making a kitchen garden using simple no-dig techniques. I'll post more pics and stories from this garden in the months to come but for now, I'm off to do a spot of planting. Happy growing!