Plants Out of Place
In academia, a weed is simply a plant out of
place. A corn plant in a soybean field is considered a weed. In practicality,
weeds complicate almost every aspect of our farming business. Some weeds are
actually a useful indicator of pH or fertility issues. We know how to get rid
of them, if the timing is right. Much of what we do as organic farmers is
managing the soil weed-seed bank with our farming systems, but we have steel
for the ones that get by us.
To understand weed-control options, we must
start with the weeds' biology and reproductive capacities. In general, annual
weeds produce lots of seeds; biennials less. Perennials use shoots and roots to
reproduce, but there are exceptions. Some are monocots (grasses), some dicots
(broad leafs). Some germinate in cool
soils, others as the soil warms. Some like it wet, some dry. All shades of gray
come in for soil pH and fertility. When you put all these combinations
together, there is something for us to combat throughout the year.
Most seeds have a protective coating and are
programmed to stay dormant until conditions are right. They can sit idle in the
soil for years—even decades. This accumulation of seeds is called the seed
bank. Researchers have found that in perennial pasture soils, there may be as
many as 150,000 seeds per square meter.
We can reduce the number of seeds that
germinate by not disturbing the soil and by preventing the animals from
overgrazing the perennial plants, which shade out the weeds and out-compete
their roots for soil nutrients and moisture. In crop fields, the seed bank is
awakened by cultivation, which exposures weed seeds to light and places them at
the right depth to sprout and grow. How the seeds know this is a bit of a
miracle in itself. Knowing we have stimulated them to grow, we quickly plant
our desired crop with the idea that it will quickly emerge and shade out the
slower-growing weeds. Some more than others, but all plant roots exude
compounds that tell weed seeds not to germinate because there is too much
competition. This is called allelopathy—part of the miracle we work
with.
When our plants are in wide rows, like in the
vegetable fields, we assume the responsibility of eliminating the weeds around
them. For direct-seeded crops, like beets, beans and corn, we often create a
stale seed bed. We get the field ready to plant but then wait for the
opportunistic weed seeds to sprout and grow. With very shallow cultivation, we
destroy them, then plant our crop, knowing there will be less competition since
we killed off a lot of the weeds already.
Cattle and sheep will eat lots of weeds. In
fact, they seem to like the diversity. Livestock may consume small quantities
of some weeds considered toxic, which leads us to think it may be part of their
innate behavior to ward off internal parasites. Other weeds provide good
nutrients when young and tender but not when they get mature and rank. Cattle
and sheep can be seen stripping the seeds off the stems. It is a thing of
beauty to see a patch of spiny pigweed in a field with no viable seeds
attached, knowing they have been consumed, degraded and digested by an animal.
Blackbirds and songbirds can eat a lot of seeds in a years’ time, as well.
The Worst of
the Weeds
Two of the more insidious invaders we must
thwart are thistles and Johnson grass. We have two options to control thistles.
They can be chopped out with a hoe, but you have to cut just below the soil
surface to separate the crown from the root, otherwise they will sucker out and
send up numerous small shoots. The second control method requires the right
timing. If we cringingly wait for the classic purple thistle flowers to develop
before we mow the field, the plant hormones think seeds were produced and do
not tell the plant to sucker out and try again, but boy, it can get ugly out
there for a while.
Johnson grass is the toughest of all for us to manage, much less control. It is a perennial that both aggressively sends
out root rhizomes and makes lots of seeds if left unattended. The rhizomes can
run out many feet in all directions and are segmented into nodes. If left
untouched, one node will become dominant and send up a new shoot. If the
rhizomes are cut by cultivation, several of the nodes will become dominant,
sending up several shoots. If you mow the tops to prevent seed development, it
stimulates the plants to send out more rhizomes. We do not see much Johnson
grass in pastures, as repetitious grazing will deplete root reserves over time,
but this is hard to duplicate in
crop fields.
So, the weeds-arms race is on. We can predict
what weeds we will see each year and when they will show up. We have a plan and
the knowledge and tools to implement our weed-control strategies. We have been
doing it for generations, yet here they come again. We are making some headway
in some areas with our organic-farming techniques, but it’s tough to break the
weed-seed bank. –Mac Stone
In
Your Share
Green Beans
Cucumber
Kale Greens
Lettuce
Gold
Potatoes
Spinach
Summer
Squash
Heirloom
Tomatoes
Garlic
Recipes
Garlic
Margherita Chicken and Zucchini
Thanks to Kim, a long-time CSA member, for sharing
this recipe with us! You can substitute cherry tomatoes or a cut-up regular-sized
tomato for the grape tomatoes and any type of summer squash for zucchini here.
1 lb. chicken breast, or tenders cut into 1"
pieces
2 tsp. olive, coconut or avocado oil
2 large garlic cloves, crushed
salt & pepper
1 ½ lb. zucchini, cut into half moon shapes
1 ½ c. halved grape tomatoes
¼ c. fresh chopped basil
Parmesan cheese
Preheat skillet on medium heat. Add half of oil to
coat. Add half of garlic and cook for just 10 seconds. Add chicken, sprinkle
with sea salt and pepper to taste. Cook uncovered, stirring occasionally, until
cooked through, about 8-10 minutes. Transfer to a plate and set aside.
Cook zucchini the same way as chicken but for 6
minutes, adding tomatoes during the last 3 minutes. Add chicken back to skillet
and stir just to warm. Remove from heat, sprinkle with fresh basil and Parmesan
cheese. Serves 4 to 6
Easy Lettuce Pesto, adapted from Suburbia-Unwrapped.com
4 c. lettuce, packed
⅓ c. fresh parsley
3 cloves garlic
½ c. Parmesan cheese
½ c. walnuts
½ tsp. salt
¼ to ½ c. olive oil
Place lettuce, parsley, garlic, Parmesan cheese,
walnuts and salt in a food processor. Pulse as you drizzle olive oil to reach
the desired consistency. To serve, spread on bread or toss with pasta. Store in
fridge for up to 2 weeks or freeze for later use.
Potato
Salad with Kale and Mustard,
adapted from With Food + Love
This healthy upgrade to a heavy, mayo-based potato
salad is a staple potluck dish for one of our farm employees. Serve it warm or
cold.
8 - 10 small potatoes, quartered
3 c. kale, finely shredded
½ T. fresh lemon juice
3 T. olive oil, divided
¼ c. stone-ground grainy mustard
½ tsp. garlic powder
2 T. fresh chives or scallions, chopped
salt & pepper
Cook the potatoes in boiling water until tender,
drain, and set aside.
In a medium bowl, toss kale with lemon juice, 1
tablespoon olive oil and a pinch of salt. Massage with your hands for 3
minutes--it will turn slightly wilted and bright green.
In a small mixing bowl combine the remaining olive
oil, mustard, garlic powder, chives, and season with salt and pepper. Mix well
until the dressing is smooth and creamy. In a large bowl combine the potatoes,
kale and grainy mustard dressing. Combine well and serve warm, or refrigerate
until desired temperature has been reached.
Ginger-Sesame
Green Beans, adapted from Joy of
Kosher
1 lb. green beans, ends snapped off
1 T. olive oil
salt
1 T. tamari or soy sauce
2 T. honey
1 T. minced garlic
1 tsp. grated fresh ginger
1 tsp. sesame oil
¼ tsp. red pepper flakes
Freshly ground black pepper
Toasted sesame seeds
Preheat oven to 425 degrees F. Spread beans in a
9x13 baking dish; drizzle with olive oil and sprinkle with salt to taste. Toss
to coat beans evenly, and roast for 10 minutes. Meanwhile, combine tamari or
soy sauce, honey, garlic, ginger, sesame oil and red pepper flakes in a small
bowl. Remove beans from oven. Pour tamari-sesame mixture over beans and toss to
coat evenly. Return beans to oven and roast for 10-12 additional minutes,
until browned and starting to shrivel. Transfer to serving plate and sprinkle
with additional salt, black pepper and sesame seeds.
