Cheyenne Garden Gossip

Gardening on the high plains of southeastern Wyoming


Raised beds for better gardening

2016-6 Barb Sahl and raised bed w pavers - Barb GOrges

Barb Sahl made raised beds from concrete pavers and two by fours that are sturdy enough to sit on, saving her knees. Photo taken May 7 by Barb Gorges.

Published in the Wyoming Tribune Eagle May 29, 2016, “Got rabbits? Try raised bed gardening.”

By Barb Gorges

Rabbits made her do it.

Barb Sahl, a Laramie County Master Gardener, told me she was a ground-level vegetable gardener for the first nine years at her place on Cheyenne’s south side, but she switched to raised beds to keep the rabbits out of her garden.

There were other considerations too. Raised beds would help keep her dogs from running through the radishes and it was a way to deal with a persistent weed problem.

Sahl was also thinking about her aging knees, knowing her days of kneeling would end in the future.

With that in mind, she installed eight beds using a system of landscape pavers, then added five stock tanks.

2016-6a raised beds 2

Sahl’s dog patrols the vegetable garden in late August 2016.

Below you will find information about the history, types and benefits of raised beds in our area.

Genesis of the raised bed

The stereotypical vegetable garden has rows of vegetables. The bare ground between must be kept weeded.

An alternative is to grow vegetables like flowers, using wide beds, 2 to 4 feet wide (depending on how far you want to reach) and grow your plants more closely. This shades out the weeds and you never step into the wide beds, keeping the soil from getting compacted. The paths between beds can be mulched.

A wide bed can be planted at ground level, or with a bit of soil excavated from what will be the paths, made into a flat-topped mound. The soil in the mound will warm up earlier in spring, allowing earlier planting, though the plants themselves may still need protection from frost at night.

If the bed is amended with compost or with soil brought in, fertility and drainage can be improved.

In 2012, I tried the mound method. I had few weeds and great results. The path around the bed was deep in tree leaves collected the previous fall. However, the edges of the mound had a tendency to erode after heavy rains.

Last summer my husband and I converted to what gardeners normally envision a raised bed to be, a contained mound.

Types of raised beds

Gardeners have been inventive at using whatever is at hand to make the walls of a raised bed: bales of straw (hay has too many seeds that will sprout), wood, rock, brick, concrete block, old stock tanks. Raised beds work for flowers as well as vegetables. Sahl even has her raspberries in one to keep them from spreading.

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Wood: Raised beds can be built to workbench-level (“elevated” beds) or the sides can be as low as a single 6-inch wooden board—though that won’t keep the rabbits out. However, Sahl soon realized plain wooden boards would decompose and she would have to replace them sooner than she’d like.

Thirty years ago, raised beds using old railroad ties were fashionable, but it was found that wood preservative chemicals from that era are toxic and can migrate into vegetable plants.

Currently, “ground contact pressure treated” wood has an environmentally friendlier preservative but there is still controversy.

If in doubt, use cedar or redwood. Either, though more expensive, should last a lifetime.

Raised bed kits often contain posts with brackets that hold wooden boards. Another version I’m trying this year, available locally, is steel plates 18 inches tall and bent 90 degrees which fit around the outside corners of the bed and screw into place.

2016-6 Plastic lumber raised bed - Barb Gorges

Plastic lumber raised bed.

2016-6 Plastic lumber raised bed detail - Barb Gorges

Galvanized steel bracket.

In another bed we built 15 years ago, using plastic dimensional lumber, the corners are held together by brackets on the inside. Surprisingly, the galvanized steel has not rusted out.

2016-6 Raised bed w pavers detail

This detail of Sahl’s raised bed system shows the brackets used to hold the concrete pavers upright, connecting them to the 2 x 4s along the bottom and the top. She will put drip irrigation (the black plastic hoses) back in when planting the beds. Photo by Barb Gorges.

Pavers: Sahl used a system she found from Lee Valley Tools that starts with a frame of pressure treated two by fours outlining the shape of the bed. She made hers 2.5 feet wide by 8 feet long. Steel brackets attach to the frame and are designed to hold pre-cast concrete pavers upright. Sahl’s pavers are 16 inches square. More brackets along the top edge of the pavers attach to another frame of two by fours, making the structure strong enough to sit on. The brackets are ordered as a kit and the gardener buys the wood and pavers locally.

 

2016-6 Concrete block raised bed - Barb Gorges

Raised bed made with stacked concrete blocks. Photo by Barb Gorges.

2016-6 Converted trash can holder - Barb Gorges

An enclosure for trash cans has been converted to a raised bed. Photo by Barb Gorges.

Concrete block: Mark and I tried a concrete block raised bed for our vegetables last year, but we didn’t stack the blocks on boards like Sahl did her pavers. After this past winter’s freezing and thawing, the walls undulate. Also, for the nine months of the year nothing is growing in it, the bed looks just like a pile of ugly gray concrete—right in the middle of the view from our favorite window.

2016-6 Stock tank raised bed w raspberries

Sahl’s recycled stock tank helps contain the spread of her raspberry patch. Large holes in the bottom of the tank are necessary for good drainage. Photo by Barb Gorges.

Stock tanks: This style is simpler, but perhaps harder to find, prep and install.

Sahl uses this method and got the idea from a relative who uses rusted-out tanks in her garden.

Sahl found her own stock tanks on Craig’s list. We’re talking about the long, narrow ones made of galvanized steel. Sahl’s are 2 to 2.5 feet across by 6 or 8 feet long by about 2 feet deep. Since they weren’t rusted out on the bottom, she drilled lots of holes for drainage. If she were to do it again, she suggests just cutting out portions of the bottoms.

How to install a raised bed

Find a flat, sunny location within range of your hose or drip irrigation system.

Plan the bed’s width so you can reach the middle comfortably, and maximize the dimension of materials to be used. The shape can be square, rectangular or even L or U-shaped. Sahl left enough room between beds for her wheelbarrow.

Because Sahl has a weedy infestation of skeleton-leaf bursage, she chose to cover her site with weed barrier cloth and then covered that with bark mulch between the beds.

Under normal conditions, you would remove pre-existing vegetation as you would for any other garden, especially if you aren’t building your raised bed very high—you need to allow for root growth.

Unless your building materials are ephemeral, temporary like straw bales, be sure to use a level to keep everything square and neat looking. Get corner posts set straight and boards horizontal.

How to fill a raised bed

Sahl wanted completely different soil for her beds than what was in her yard so she ordered a load that was a little sandier, with less clay. It’s important that it is good quality, she said, and not full of weed seeds. She has grown a wide variety of vegetables in the eight years since and is very happy with the results.

If you are growing vegetables, you may want to mix in a lot of compost like that available through Cheyenne’s compost facility. In future seasons you won’t have to till, just add a couple more inches of compost, perhaps in the form of the organic mulch you use on the surface—leaves and grass clippings, etc.

For flowers, be aware that hardy native perennials do best with less fertile soil.

Accessories

Sahl has made tomato cages from concrete mesh that fit her raised beds perfectly. She can wrap them in plastic to protect the plants from frost early in the season.

Raised beds also lend themselves to the addition of trellises, cold frame covers, mini-hoop houses, hail guards and drip irrigation systems. See previous columns on those subjects at www.CheyenneGardenGossip.wordpress.com.

Details of Sahl’s raised beds, late August 2016: (clockwise from top left) onions, cabbage, raspberries, tomato, carrots.

2016-6a Gorges raised bed in JulyGorges raised bed, July 2016.

 

 

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Transplanting to the Garden

Hardening off seedlings

Harden off seedlings before transplanting them by starting with just a few hours in the sun each day, gradually increasing the length of time.

Published May 20, 2012 in the Wyoming Tribune Eagle, “Tomato Time! Here are some useful tips for successful planting and transplanting.”

Cheyenne’s average growing season weather is very pleasant. It is just those pesky extremes averaged in, those bursts of hail, hard rain, wind, cold and heat that make successful gardening tough.

Even though this spring has been unusually dry and warm, I’ve been expecting the other shoe to drop—snow. Did you gamble on more warm weather and put your plants out before Cheyenne’s recommended planting date of May 24?

Remember, there is still a 10 percent chance of frost until June 8, so make sure you have your old sheets at the ready to cover your plants on a cold night. Or try a product called floating row cover, which is spun polyester fabric available at many garden supply centers.

Timing

There are plenty of flowers and vegetables that weather a little frost–tulips, daffodils, crocus and other early bulbs and early perennials. Keep in mind for next year that pansies can be planted as early as April 15—and they bloom all summer.

Among the vegetables, the cole crops such as cabbage, broccoli, and cauliflower, do fine with a bit of frost, either seeded directly or as transplants that were started even earlier indoors. No wonder cabbage-based dishes are a feature of ethnic cooking in cold, northern, short-growing-season countries.

For a list of recommended planting times for vegetables in Cheyenne, visit the Cheyenne Botanic Gardens or go to its website, www.botanic.org, and look for the Garden Tips sheet titled “Planting Schedule.”

By the last week in May, it should be safe to transplant everything else and sow seeds for plants that don’t need a head start, such as marigolds, squash and pumpkins, or those that dislike being transplanted, such as sunflowers and nasturtiums.

Some Cheyennites wait as late as the end of the first week in June to put in the heat lovers: tomatoes, peppers and eggplant.

Choosing plants

To find out how to choose plants at the nursery, I talked to Jessica Friis, the assistant education director at the Paul Smith Children’s Village at the Cheyenne Botanic Gardens. She is a graduate of the landscape management program at Brigham Young University and manages the Village’s gardens.

“Ideally, you’d want smaller plants that aren’t root-bound. It’s hard to find that. Find some that haven’t bloomed yet. Make sure they have been well-watered and the soil feels moist,” she said.

Businesses other than nurseries can sometimes do a good job of plant care, she said, but be careful.

As you may know from previous columns, I’m challenging myself to grow tomatoes from seed, “Gold Nugget” yellow cherry tomatoes, and an annual flower, cosmos. I don’t feel so bad now, knowing they won’t be flowering when I’m ready to transplant them outdoors.

When picking out perennial plants that will grow well here, look for those marked “Plant Select.” This is a breeding program partnership between Colorado State University, Denver Botanic Gardens and growers. This label is an indication that the variety will perform well in Colorado, which generally means it will also thrive in Cheyenne. You can find them in Cheyenne nurseries.

Hardening off

Chances are that you are buying plants that were on display outdoors. If not, or you grew your own, give them an opportunity to gradually adapt to sun and wind, a process known as hardening off. Put them out for a couple hours one day, and a couple hours longer the next, increasing exposure over several days, making sure plants don’t wilt.

Transplanting techniques

Friis has a few tips for successful transplanting.

For annual flowers and vegetables, turn the garden bed first (break up the soil crust), 6-8 inches deep. Then water it a day or two before you plant.

Also: “Water plants really well before planting, getting them soaking wet,” she said.

When you dig a hole for a plant, Jessica recommends making it twice the width of the root ball so the roots have an easy time growing.

Make sure your hole is deep enough the roots don’t fold back on themselves.

“We bury plants a little deep, up to the bottom set of leaves,” said Friis. “It gives a little extra protection.”

On tomato plants, you can even bury the second set of leaves.

Hold the plant over the hole at the proper height and fill in around it with dirt.

For plants that are root-bound, Friis said there is a debate about whether to “tear” the roots first.

“Try to loosen them up without breaking them,” she said.

When pulling annuals out in the fall, she said it is easy to see that roots that circled round and round in their pots before planting never grew any further out all summer—and neither did the plant tops.

If not root-bound, keep the root mass intact as much as possible to lessen transplant shock. Otherwise, a plant has to re-establish all those little root hairs before the green part can start growing again.

For seedlings in peat pots, the pots don’t decay much in the soil here and can inhibit growth. Break off the bottoms if the roots haven’t penetrated them yet. And don’t leave the rim of the pot sticking above ground—tear it off.

Spacing

In Cheyenne, we should space flowers more closely than recommended, Friis said. Since we have such a short growing season, flowers won’t otherwise fill in the garden completely until nearly the week before first frost (September 20), so planters at the Children’s Village are packed thick.

Fertilizing

“We use a slow release fertilizer, like Osmacote, applying it once a month,” Jessica said. “Or you can use a liquid fertilizer every week to two weeks.”

She fertilizes closely packed planters every week. However, many perennials, especially natives, require very little fertilizing other than decomposing mulch.

Mulch

Don’t forget a layer of mulch for all your plants. Bits of semi-decomposed plant material, including leaves and grass clippings (don’t use fresh clippings though), will keep the soil from drying out too quickly. It also will shade out the weeds. Don’t leave mulch touching plant stems.

Water again

And finally, water well each day for several days, until plants are established, but water carefully so plants don’t become mud-bedraggled.

Sowing seeds

Read the seed packet directions to find out how deep seeds need to be planted. Try making a wide bed vegetable garden to avoid compacting the soil. See the Garden Tips sheet at www.botanic.org or pick it up at the Cheyenne Botanic Gardens.

Don’t hesitate to thin seedlings as recommended, since crowding will decrease your yield, as a friend of mine discovered last year when she harvested the skinniest carrots she’d ever seen.

I collected seeds from last year’s flowers: marigold, feverfew, penstemon and gaillardia. Since the seeds didn’t cost me anything, I can sprinkle them generously this spring where I’ve pulled the winter leaf mulch away around the fading tulips.

I will water the seeds well and crumble a thin layer of old leaves over them for shade. My soil does not have a tidy, smooth surface so enough seeds always find the right spot to take root.

Rabbits

Do you have trouble with rabbits snacking on your new plants? Friis has found that a short, rabbit-proof wire fence works better than deterrents that must be reapplied frequently.

Next month we’ll take a look at other ways to mulch, water, fertilize and maintain a garden.