Our new house site has a grade of around 10% (rise/run = 1/10)
We're intending to grow loads of veges around the house, employing the mandala garden design most likely.
Can we put our vege gardens on a slope like this no problem?....or is growing on level ground much preferred for some reason?
I ask because we are about to get the earth mover machine in and I can see we have the option of creating a series of flat terraces, or retain the original slope of the site. I would kind of prefer to NOT to have the terraces, simply for site simplicity, but i don't know whether putting vege gardens/mandalas on a 10% slope can be problematic or not..?
I think that one problem with gardening on a slope is that water drains down to the lower parts, leaving the upper parts dry. If you could put in swales on contour at the top of the garden, that would help slow water down and let it soak in. You could also plant things that need less water at the top, and the more water hungry plants at the bottom. But I think that a swale would be much better. Slowing the water down and letting it soak in is the key to having a resilient garden. You can also put a swale at the bottom to help retain more water and keep it from running away down the hill.
Hope that helps! Good luck with your new home and garden.
Don't know if I personally would go with the Mandelas on a slope I would be more inclined to think of terraces particularly if you have a south facing slope to take advantage of the sun and create many different microclimates
Living in Anjou , France,
For the many not for the few
I'd tend to go with terraces, too, since they seem like an equal option. Swales can do much to reduce water loss. But many other activities you'll probably want to do to improve the soil -- layering organic matter on top and that sort of thing -- will be easier on a flatter surface.
In my front yard next to the street slopes towards the center. When heavy rain falls it pools in middle of the yard, right up to the lowest edge of the garden beds on these sloped sections. These last two springs, while most gardeners in my area have had wide spread drowning of their plants, mine have remained healthy because the water was able to drain fast enough. So there are some very sound benefits to slope in a garden.
My inclination in your circumstance would be to take advantage of the earth moving equipment. There's a reason why so many ancient cultures put the years of hand labor into building terraces for farming. If you don't do it now, will you have ready access to the earth moving equipment, and will the equipment be able to access the land to shape it without destroying other projects?
If you really don't feel these kinds of earthworks are for you, I think if you just lay out your garden in rows on contour you would get similar effects, though much smaller. If you add amendments that raise the soil level (tilled in or top dressed) the garden bed itself would be a small berm creating a micro-swale upslope. Simply keeping thick vegetation in the beds with shorter (or no) vegetation in paths between would cause water to slow and pool a little right above the garden bed.
The more texture you add to your slope, through earth works that change the shape like terracing or swales or through planting strategies that cover the ground in dense vegetation, the more opportunities you have to slow and capture water. In all but the wettest of circumstances, keeping water on your property, and in your soil is one of the best things you can do to support healthy soil life. If you have healthy soil you can hold more water in the ground itself than any rainwater catchment system.