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How to Plant Garlic & Add Perlite to Raised beds?

Q. This year will be my first attempt at growing garlic. In one of your previous questions of the week, you state that "the best way to plant garlic is right in the ground." Since you force so many of your callers to reveal whether they grow in flat earth or raised beds, I thought I'd turn the tables and ask you to clarify what you mean by "ground". Should I plant my garlic in a raised bed or flat earth? Obviously, my raised beds contain the loosest, richest soil, but I'm afraid of the winter cold.

---Kelly in Point Pleasant, New Jersey; a proud member of WHYY, WBJB, WNYC, KRVS, and NJTV!

A. Wow; thank you for all your support of Public Broadcasting! Now—I think the article you reference discusses the possibility of growing garlic in containers, which I don't recommend, even though I got away with it the year I tried it personally. (It was a nicely mild winter, and I have learned that you can't count on those.) There are way too many variables…

If you want to try anyway, the container would have to be as big as possible—at least a foot and a half high, preferably taller; and nice and wide as well. That's because small containers freeze fast—and the roots of plants in small pots are always going to be closer to that freezing air than if they were in a big pot. You want a solid six to eight inches of space between the outside edge of your plantings and the sides of the container for an attempt at overwintering outdoors.

The container would have to have excellent drainage; and be mostly filled with a really loose, light soil-free mix (plus compost and ideally some added perlite). None of your crappy clay or other nasty garden soil; it would smother the poor plants over winter. And it has to be a REAL container—no trailer park, five-gallon-bucket gardening!

Then if you're in a climate similar to the greater Philadelphia area (aka USDA growing zone 7 or so), the container should be positioned in a protected area—near a structure but open to sunshine and rain. As you get further South, the container can move more out into the open. I wouldn't attempt it where winters are really cold. In those areas, it's much better to 'borrow' a plot of ground somewhere. (And no, it can't just stay inside; garlic has a chilling requirement that's hard-to-impossible to duplicate indoors.)

Now—about those raised beds

(Yes, I'm actually about to answer her question. I know you don't expect that, but I'm parked at a meter.)

In New Jersey, the Philadelphia area and South, raised beds are ideal for garlic because of their superior drainage. And garlic grows deep enough that freezing isn't a problem if you follow the general rule of planting the individual cloves {quote} "six inches deep", which means four inches of soil on top of a two-inch long clove.

Further North, plant a couple of inches deeper if your soil is light enough, but more importantly, mulch the bed with two inches of well-shredded leaves (NOT whole leaves; they MUST be shredded) after the soil freezes hard for the season. Not before! The goal of winter mulch is always to keep the soil from heaving during winter warm spells, so you let the soil freeze and then cover it until Spring to prevent mood swings at the soil surface.

You'll find much more garlic growing info in these previous Questions of the Week:
Let's Get Some Garlic in the Ground!
How to Grow & Harvest Great Garlic & How to Make Garlic Powder
It's Fall; Time to Plant Garlic, Pansies & Trees (oh my!)

Q. Now we have a somewhat-related question from the show's Facebook page. Yvette, near Albany writes: "I heard you recommend perlite on a recent show. I don't till my raised beds; so how would I add the perlite? Can I just mix it into the two inches of compost dressing I add in the fall and spring?"

First I have to point out that she has wonderful garden habits. Tilling is very bad for soil; it releases nutrients into the air and creates massive amounts of weeds—and if the soil isn't perfectly dry, also kills earthworms and damages the soil structure. One of the biggest benefits of raised beds that are made correctly—that's four feet wide or less—is that you never have to step on the soil to reach your plants and so you never compact that soil and don't ever have to till it.

And two inches of compost applied to the surface every season—as opposed to being tilled in—is ideal. (And she's doing four inches a year! Trying to make me look bad!)

But, unfortunately you CAN'T just add soil-lightening perlite to compost toppings and get the kind of results you want. Ideally, perlite—a mined volcanic glass that is my favorite garden amendment (after compost, of course!)—should be mixed into the top foot of your soil to lighten it up and improve the drainage.

So you have to decide: if your beds are draining fine, I would just mix some perlite in with your compost applications. It should work its way down slowly over time. (And as my grandmother used to say, "couldn't hurt!".)

But if your beds have gotten 'heavy' over the years, I suggest picking one bed a season and working a LOT of perlite into its soil—twice what you would think you need, so that you don't have to do it again. Then when you're done, use the 'stale seed bed' technique to kill the weeds you have unearthed by tilling or turning the soil.

Level the soil perfectly after you're done mixing in the perlite and water it a little bit every day for two weeks. Then use a super-sharp hoe to slice the little heads off all the weeds that have emerged from the dormant seeds you disturbed. Then you've got a renovated, weed-free, better draining bed….

….in which to plant your garlic!

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