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New Beginnings: A vegetable garden in Colorado
Carol O’Meara is driving her pickup truck bound for
llama manure. That’s less jolting if you realize that O’Meara is a dedicated
vegetable gardener. Only the best will do for her garden, and one of the best is
Along the eastern foothills and plains of Colorado, a
vegetable garden doesn’t come easily. Every year would-be gardeners put out
their spindly tomato plants too early and suffer a cold snap. Or they watch
their spinach bolt on a blistery hot day. It’s either too cold, or too hot -- or both
-- all in the same day. Then, of course, there are the winds. Not to
mention the hard-packed clay soil.
Growing vegetables isn’t for the fainthearted, but
neither should it be impossible. With the right soil amendments it’s possible
to grow a garden you can crow over. It just takes some planning.
“About 80 percent of plant problems are caused by bad
soil,” says Carol O’Meara, who is horticultural assistant for Colorado State
University Cooperative Extension. “But I wouldn’t get too enthusiastic right
away. Adding three to four inches of organic compost is enough the first time
you’ve broken ground. You just want to change the texture of the soil a
little. We have such heavy clay and alkaline soil that we need compost to hold
air and water.”
Conventional wisdom dictates that you build a compost bin
and toss every vegetable and yard scrap to be baked in the sun. What results is
a fluffy mixture that when added to aged cow, horse or llama manure makes
perfect compost. If it could only be so easy.
A CAVEAT TO ADDING MANURE
Recent news reports are warning gardeners to be careful
about the kind of cow manure they choose. The E.coli bacteria is present in any
animal manure, and if it hasn’t been well aged (a year is considered about
right), then tender leafy spinach and lettuce may harbor the bacteria.
Wash all produce well in a sink of water and never eat
produce straight from the garden. This holds for any organic produce you buy,
whether it’s at a supermarket or farmers’ market.
Get to know the person who sells you manure and ask
questions. Find out how long the manure or compost you’ve purchased has been
aged. If you buy compost that has manure already added, don’t add more.
Even if the manure is well aged, there’s another caveat to adding cow manure
in your gardens. Most feedlot and several dairies have
their cows penned closely together. The urine of cows is heavy with salts, which
collects on their manure. You may be salting your garden and ruining the soil.
That’s why Carol suggests going lightly with the manure, and that’s why
she’s seeking llama manure. Animals like llama and horses are allowed to graze
and wander. They’re also not fed salt to increase their meat or milk
production. That makes their manure valuable.
So you’ve found a wonderful mix of compost and tilled it
into your soil. You’ve changed the texture of the soil, so that the tender
vegetable roots can reach downward and form strong roots. But adding compost is
not the same as adding fertilizer; compost simply alters the texture of the
soil. Vegetables demand nutrients so it’s hard to hope for much production
without adding nitrogen and phosphorus, along with trace minerals.
Yet, another warning. “Over fertilizing is a problem,” Carol says. If a little is good than a lot is better. Not so. Read the
instructions carefully on your fertilizer and don’t over-do. If you want to go
organic, Carol suggests blood meal for nitrogen and bone meal for
phosphorus. We generally don’t need potassium in our soil, it already has
For nitrogen, don’t forget about cover crops over the
winter. “It’s even better to use a cover crop that is nitrogen-fixing,”
she says. When planted in the fall, that crop of rye, clover or peas will create
nitrogen in the soil. After you till it under, you’ll have first rate
HOW TO CREATE A GARDEN
Here’s how Carol creates her garden. After the
tilling and fertilizing, she sets a drip irrigation along her rows. Then a weed
barrier cloth (she also recommends newspaper) goes down and she mulches with
lawn clippings that are pesticide-free. That’s it. There’s little weeding,
water is conserved and the plants don’t bake in the heat.
But that’s not the only way. Ramona Clark, a Boulder Community Gardens leader, prefers a raised bed. These high beds are so enriched with humus
that she can grow more produce in a small space and have succession planting.
“Do double digging if you can,” she says, “and layer compost and old
manure.” She adds fish emulsion or blood meal as well as bone meal.
And as for manure, her rule is simple: “The more stomachs
the animal has the better. Horses just have one so you’ll get a lot of weed
seeds. Cow, bat, rabbit, chicken, sheep are all good. But you want it old and
Estee Fleming, who manages the Denver Community Gardens at the Denver Botanic
Gardens also likes raised beds: “They’re great for people with bad backs and
wheelchair gardeners. But they do dry out quickly, so be careful.” She likes
sea kelp for organic fertilizer.
Like Carol, Estee believes that cover crops planted
over the winter are essential for added nitrogen and preventing soil erosion.
Estee plants rye and buckwheat but says she is experimenting with others. She
also recommends a thorough clean up in the fall. Unlike perennial beds, where
the seed heads can provide a winter habitat for the birds, vegetable garden
waste provides only a safe harbor for pests.
It’s imperative to get rid of any diseased debris from
the nightshade family – that includes tomatoes, potatoes, peppers and
eggplant. Leaves infected with the flea beetle will shelter those pests.
That’s another reason to practice crop rotation with vegetables, because many
pests live through the winter in the soil. You can break the cycle of
infestation by moving your crops to a new location each year. Most farmers rely
on a three to four year cycle.
Two last tips: never add sand to clay, it just makes adobe
soil. And never buy Colorado peat; harvesting local peat destroys the mountain
environments and is a poor choice of a soil amendment. Other peat products are
State University Cooperative Extension
Gardens at the Denver Botanic Gardens