This morning petrichor was heavy in the air. Petrichor is a smell so strong; you can almost feel the texture gritting against your skin. It's a mixture of ocean and dust. But more than that. Petrichor is the smell rain makes after dry, grimy, hot summer days.
It's unusual to experience petrichor here, as it seldom rains in summer and never in June. At least not since we moved to the farm nearly ten years ago. It is an unusual year for weather. I expect unusual will soon be the new norm.
Most years, the rain stops on or before May first. There are a couple of rainy patches near midsummer and again at the end of August, but these showers usually miss the farm. It will rain at the neighbours and across the road, but not here. One of the things we strive for is low maintenance farming; farming without irrigation or rain in a Mediterranean climate. Most of the experiments on the farm have been focused on the assumption it won't rain in the summer. We've had great success with this. There are a few parts of the farm that are entirely irrigation-free and produce a decent crop even on poor soil.
We've grown chickpeas, peas, soup peas, kale, squash, hot peppers, sunflowers, woad, flax, and tomatoes without irrigation or rain. Pretty darn neat. This year, we've been experimenting with different row and plant spacing as well as potatoes. But the rain has skewed our results - not that we mind - so we'll have to try it again next year.
How are we growing these without irrigation?
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I've learned a lot from permaculture. The world domination gardening videos are a great resource filled with different techniques, how and why they work, and how to build them. The last video is my favourite. It's about adding texture to the landscape to create warm pockets.
Finding microclimates that are already moist
There's a section of the farm that is quite moist most of the year. There's an ephemeral stream and in the winter, the whole area floods. By deepening a hollow that was already there to create a pond we capture some of the winter rain that would otherwise pass us by. The stream we made curvier and planted willows and other trees to help capture moisture and hold it in the soil. Trees are also great at capturing dew and can often create their own rain on moist mornings. Since the ground is too wet to till until May, it is a good spot for warm weather crops like beans, corn, squash and sunflowers.
Making our own microclimates
Terracing adds texture to the landscape like nothing else. It's also great for reducing the speed that water runs off the land. Storing moisture in the soil during the rainy season is possibly the most efficient way we've found to grow without irrigation. Somehow terracing reduces the fluctuation in temperature.
airwells to capture dew
Capturing dew is an essential tool to irrigation-free farming. An airwell a great help with this. About three years back we transplanted 100 fruit trees at the start of what turned out to be one of the driest summers on record. We moved the trees to the spot with the most drainage and worst water retention soil on the farm and gave them nothing to drink. Not even watering them in when we moved them.
Two-thirds of the fruit trees were given an airwell. A small, dry stack, rock wall. One third was given nothing. Of the latter, we have on tree surviving. But the trees with the airwell are growing strong. Through extreme heat, drought, cold, and all sorts of crazy weather, we have only lost two of the 60-odd trees. The only difference is the airwell. We were shocked by just how much difference it made.
Even making texture on the soil increases dew collection. Molding up potatoes left furrows between the rows. I was surprised to see just how much dew collected in them.
One thing that isn't working is mulch. Mulch works wonders if it rains at least once a month, but by the end of the second month without rain, it seems to do more harm than good. By the end of month five, only well established perennials with high dew collecting abilities like rosemary, sage, and lavender can survive mulch.
Mulch covers the soil and prevents moisture loss, but it also prevents moisture penetration. Once the mulch dries out, the dew that runs down the stems of the plants, cannot enter the soil for later use. By the time the soil is warm enough for the invisible beasties to break down the mulch into soil, the mulch is too dry to sustain them.
Looking at our local forests, one can see why mulch doesn't make sense here. Mulch works well where the soil is built through layers of detritus like leaves and grass. But here, when one watches a pioneer area, the soil isn't formed that way. The cottonwood and alder grow on poor, but moist soil pockets, then when they fall, the logs quickly rot to create better soil. The leaves do very little except provide food and shelter for animals who fertilise and build soil that way. For this reason, I suspect Hugelkulture will be a useful tool in our area. Something to try in the years to come.