Yesterday, I led a garden planning workshop with Preserving Traditions at the Pittsfield Grange. A couple of questions came up more than once, so I thought I’d answer them here in case they interest anyone else.
What material should I use for my raised bed’s walls?
I’ve used both composite decking material and 2″x8″x8′ standard (untreated) pine lumber. The composite has bowed out over the years but the pine hasn’t. I’m not sure how long the pine will last, but after
3 6 years in my Michigan zone 5b garden, it’s not showing much wear or rot. It’s also cheap, easy to find, and there’s no worry about leaching chemicals, so it is my preference for all my new beds. YMMV, especially if you live where it’s warm all year and termites are a problem.
Do I need to dig up the sod/soil before building my raised bed?
No. If you put at least 6″ of dirt and compost in the bed, it will smother all the grass. The grass will compost and become worm food, and your deeper-rooted plants will soften the hardpan. Save your back! Let the plants and worms do the work!
What soil should I use in the beds?
You want “garden blend” soil, which is half topsoil and half compost. Plants need the minerals of the dirt AND organic matter – don’t use just one or the other. You’ll need one cubic yard to fill a 4’x8′ bed 6-8″ deep.
Where should I get soil?
If you’re near Ann Arbor and you only need a couple yards of soil, I’d order it from Lodi Farms. They’ll deliver small loads at a decent price. It will have some weeds in it (all bulk soil does) but they’re easy to remove. For larger loads, other places, like EZ Landscaping, are probably less expensive. The soil is all more or less the same quality, and all good enough to get started with.
Don’t raised beds dry out really fast?
I water mine deeply about once a week – twice if it’s really dry, not at all if we get a good rain. They seem to do just fine and they don’t “bake” any faster than the rest of the yard. And because the soil’s so loamy, it doesn’t get compacted like the rest of my clay yard does.
Is it better to put all the plants of the same family in one bed, or spread them around?
I like putting them into one bed for two reasons: it makes crop rotation easier, and similar plants often need similar protection. So, I can fence the beans easily, and cover all the brassicas to keep out the caterpillars. Other folks like mixing up the plant families to explore companion planting, or to prevent pests and diseases from moving like wildfire through all the plants of that family. It’s up to you – both approaches have advantages!
Do I have to worry about crop rotation this year? I’m getting overwhelmed!
Personally, I think it’s much more important to get out there and start your first garden than to worry about rotating crops your first year or two. Crop rotation is certainly a concern as you think about long-term sustainability. If you plant the same crop in the same place year after year, it will deplete the soil of its favorite nutrients, and it’s possible that diseases and pests will build up in the soil. So do think about it…but if it’s too much for this year, don’t sweat it.