Making a swale

I’ve made a couple of new swales recently and started a third, so thought I’d document the process.

I had a lot of asparagus to plant out and wanted to put them on a swale mound. Here’s the first swale. It’s about a metre and a half long, 40 cm wide and 30 cm deep:

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The asparagus are a bit hard to see. I’ve planted dandelions in between them, which are easier to see (the flat rosettes). The day after I took the photo the dandelions disappeared, courtesy of the rabbits. I put wire over them and they grew back good as new. Can’t keep a good dandelion down! There’s a variegated mint doing well at the far right. Rabbits don’t like mint, it seems.

At the outer edge of the swale mound there are four Strawberry Guava plants. They should grow into shrubs about a metre high with tangy red berries.

The second swale is about the same size and sits at the lower edge of a gravel path. It fills from water running off the path. I’ve planted more guavas at the base, Cherry Guava this time. They’ll get a bit taller, but I’ll keep them to a metre or so. In between them and on top of the mound are a couple of oregano plants. They should sucker and spread along the swale, maybe even grow down into it.  On the far right is a Buddleia—a Butterfly Bush. Circles of wire surround everything until it’s established. Pesky rabbits again!

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I’ve just finished the third swale. Like the others, it’s on a slope. I had just a few asparagus plants left and wanted to get them planted before they go dormant for the winter.

Since these are small swales it’s not really necessary to mark out the contour; trial and error is pretty much OK. First job is to dig out the ditch by hand and rake the soil into a mound on the lower side. Then I cover the mound with cut branches sloping away from the swale. I’ve used meleleuca here because it’s no good for firewood as it’s too soft, and it rots easily, so will add carbon to the soil fairly rapidly:

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Then I deepen the swale and rake the soil over the sticks. If I have extra soil I’ll add it, too. I could go on adding sticks and soil, making the mound higher and higher, but while sticks are plentiful around here, soil is not (unless I want holes everywhere). The sticks are supposed to deter the rabbits and blackbirds from digging up the soil on the mound. It sometimes works:

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You can see water in the swale. I fill it frequently as I’m going, just to check the levels. Mostly the ends will be the spots that need adjustment, building them up so that water doesn’t flow out. It’s looking pretty good:

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Finally, I cover the swale with mulch. I’ve used casuarina needles here, because I have a huge supply:

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It would be ideal to be able to broadcast seed into the mound at this point. Something like clover or vetch—something that would hold the soil in place and maybe provide nitrogen, but the rabbits would eat the seedlings down in a flash.

I might use yarrow. It spreads by underground rhizomes and the rabbits usually don’t touch it*. I can dig up a few clumps and plant them out, protected with wire, till they establish. I’ll put the remainder of the asparagus in later this week and that will be the end of about 2 dozen plants I grew from seed last year.

This swale is a bit over 2 metres long and I estimate that it will hold about 80-100 litres of water when full. I won’t put any chook poo compost on it until the asparagus spears are starting to appear in spring. They won’t be big enough to eat this year but my older plants are in their third year of harvesting so I can afford to wait.

* I once found a dead rabbit with a wisp of yarrow poking out of its mouth. I can’t believe that’s what killed it, but it would be nice to think I’m growing something that would. They do eat down the flowering stems though, but don’t seem to browse the leafy rosettes; not excessively enough to notice anyway. It annoys me because the flowers are rather attractive en masse:

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12 Responses to “Making a swale”

  1. narf77 Says:

    Rabbits might not like mint but wallabies do. I had a lovely chocolate mint that suddenly disappeared around about the same time that the wallabies started grazing my potted plants. Where did you get your strawberry guava’s Bev? I remember guavas as being particularly hardy little guys back when we lived in Western Australia. I don’t think I have seen them around here.
    EXCELLENT tutorial as we have tonnes of tea-tree that can’t be used for burning (too much ash) so despite the rocks in our soil I am going to give this a go. People just don’t “get” the frustrations of living in the country and trying to garden edibles (even non-edibles are edible to the natives!). I remember being one of those ignorant city folk who pooh-poohed my friends negativity about her garden right up till I moved here, learned that vinca, forget-me-knots and boneseed are NOT just pretty, they are invasive and pains in the derrière and that native animals won’t eat them (thinking of turning my ornamental garden into a forget-me-not and vinca garden…at least they will survive 😉 ) and anything that you DO want to grow gets scoffed overnight. What with the possums, the wallabies (who now come for cheese sandwiches that I throw out for our small cat population that we are managing that eat the rats, mice and rabbits…) and anything else that feels like dropping in and freeloading for a while country “gardening” has rendered this optimist an optimistic pessimist…but still we try don’t we? 🙂

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    • foodnstuff Says:

      The strawberry guavas came from a friend, at least a bag of fruit did and I grew all my plants from the seeds. I have a plant put aside for you, plus one of cherry guava, for sending with the pepino, whenever the cuttings decide to grow roots. They’ve been in so long, I think they’ve forgotten how.

      I tolerate the rabbits, ‘cos I think eventually they will become an important source of protein around here, when the neighbours finally realise that with oil running out, agriculture declining and supermarkets empty, they might just need some substitute for their daily steak.

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  2. k8heron Says:

    Great bog – thanks for showing your swale making process.
    Just a query about using Casuarina needles for mulch – I always thought that they were allelopathic or is it the fine/shallow roots that outcompetes under Casuarinas?

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    • foodnstuff Says:

      Oh, blow….I did know about the allelopathy, but had forgotten. It probably won’t be a huge issue here because it’s only a thin layer and it might stop the yarrow from over-running everything. The needles under the actual trees are inches thick and nothing grows there. I’d say there’s a fair amount of competition from the roots as well. Thanks for reminding me about allelopathy, I must look it up and find out more.

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  3. Ray Says:

    Had never thought of small scale swales. What a neat idea. Thanks for the idea.
    By the way, there are supposedly reasonable levels of both terpenes and phenols in all parts of casuarinas – roots, wood and leaves – which, in large enough quantity, would inhibit any other growth. This is probably why one often sees casuarinas in monotypic stands. Nevertheless, in small quantities I wouldn’t have thought casuarina mulch would be much of an issue. I’ve used it on a small scale and haven’t noticed any problems.

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    • foodnstuff Says:

      I was sort of forced into small-scale swales by not knowing anything about permaculture techniques when I set out the garden, and not realising that the compacted clay soil on the sloping site wouldn’t absorb rainfall quickly. They’ve been good, however. I’ve dug one behind each fruit tree and I can fill them with water in dry summers, which is much quicker than putting on a sprinkler slow enough to soak the water in.

      I’ve found casuarina mulch in small quantities is OK, too.

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  4. linda Says:

    I also didn’t think of doing smaller scale swales and this tutorial has given me a few ideas now. I don’t think that yarrow killed the rabbit-have read of people giving it to their bunnies as a treat.

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  5. Chris Says:

    Good work. I’m always an advocate for swales, and definitely small ones when experimenting with what works. Came to the same conclusions as you with slopes and all that precious water running away. Wish I could dig more, but my one year old is quite the handful and wouldn’t sit still long enough for me to concentrate on what I’m doing, lol.

    In the meantime I’ll just admire yours. 🙂

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  6. lindabrown573 Says:

    Love the idea of swales. I have my chicken coop at the bottom of a slight hill. I’d like to be able to divert some of the water going through. I’m in deep south in La so not too wet.

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    • foodnstuff Says:

      Hi Linda, a swale to intercept the water would be a good idea and if you put it close to the chicken coop and plant the mound with food for the chickens or medicinal plants for them like wormwood, then it’s easy to pick the plants and put them straight into the coop without having to walk far. Relative location (putting things right where they’re needed), is one of the permaculture principles.

      Maybe you could even put it right next to the coop and the chickens can peck their food through the wire, saving you even more energy 😉

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