AS PROMISED: On the public-radio show (available anytime as a podcast), I answered some of your recent Urgent Garden Questions. The topics ranged from how deep to build a raised bed for vegetables, to a whole range of crabapple inquiries: What’s the best crabapple variety for jelly, the crabapple with longest-lasting fruit, and more. My sister Marion Roach Smith provided the assist with the Q&A, and even brought along some challenges of her own.
Q. Everybody’s getting their vegetable gardens going, and there were multiple questions about raised beds in particular—such as this one from Tracey, who was building new ones at her garden:
How deep should a raised bed be, and what is best to make them out of?
A. I recently did a story about hugelkultur, building raised beds out of fallen wood debris such as logs and branches, but I suspect Tracey wants the more conventional solution, which is what I have used to grow vegetables in my garden the last 20-plus years.
I like 10-inch-deep raised beds, but 8 inches is also absolutely fine, and of course saves on lumber. You want a 2-by board thickness, so we’re talking 2-by-8’s or 2-by-10’s.
I recommend choosing a naturally rot-proof wood that is available locally. Here in the Northeast for me that means locust, for instance, or Eastern red cedar. If you can track down a local mill you can get boards that aren’t as finished as lumber used for more formal carpentry projects—meaning not all perfectly planed on both sides, but slightly more “rough-cut.” These boards tends to be thicker than other lumber (closer to true 2 inches thick) and also less expensive.
If not, ask at your lumber yard or building center or big-box store which material they stock that has natural rot-resistance, and hasn’t been treated chemically.
You can also use any other material you wish to make the walls of the beds, from stone to cinder block to bales of straw to synthetic “bricks” and “lumber” that are made from recycled soda bottles and so on.
Q. It’s barely crabapple bloom season in our area, but there has been an uptick of questions about those great four-season trees. Reader Alan emailed to ask about how to sort through the daunting list of crabapple varieties: What are the key features he should look for?
A. No matter where you plan to grow a crabapple (which are hardy from Zones 4-7 or 8, not in the hottest zones), the trait you want to ask about first is disease resistance. Crabapples can suffer from issues from apple scab to cedar apple rust, so you want a resistant variety.
After that, there are aesthetic considerations: flower color (a range of pinks from dark to light, including purplish ones, and white, of course); tree shape (rounded, columnar, shrubby, etc.); fruit size and color; and even leaf color (some have a reddish-cast to their foliage).
This crabapple article from the archives includes more detail on shopping for crabapples, plus links to regional lists of preferred crabapple varieties.
A. The ones usually recommended for making jelly are of course those with large fruit—like an inch and a half or 2 inches across (after about 2 inches you’re an apple, technically, not a crabapple). ‘Dolgo’ is often suggested, and ‘Callaway,’ and I love ‘Ralph Shay’ (one of my young trees, abovr) because its shiny red fruit are really long-lasting in the landscape.
Q. Pam wrote in to say: “We are looking for a crabapple variety that has long lasting fruits.”
A. Those lists I cited above, in my archive crabapple article, will help Pam find the right variety for her area. Another tactic: She can also do a web search for her area (a state, or Midwest, for instance) and crabapple and the phrase “persistent fruit,” which is what it’s called officially.
Again: Never select a tree for just an ornamental characteristic (such as persistent fruit) at the expense of getting that built-in disease resistance.
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MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its ninth year in March 2018. The show has won three silver medals for excellence from the Garden Writers Association. It’s produced at Robin Hood Radio, the smallest NPR station in the nation. Listen locally in the Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) Mondays at 8:30 AM Eastern, rerun at 8:30 Saturdays. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).