Harrows – Organic Weed Control


I’ve been using the harrow more and more over
the rotary hoe. It seems to do a better job and I seem to
be pretty happy with that. Harrows, like rotary hoes, are an important
source of early season weed control for organic farmers. After getting the crop planted in the ground,
it’s used typically four days after planting is when I want to be back out doing something
and typically it’s running the harrow over the ground. Whereas corn and soybeans are planted at depth,
weed seeds emerge from shallower in the soil profile so until that corn or soybean germinates
and nears the surface of the soil, weeds can be killed with light tillage implements like
harrows, rotary hoes or tine weeders. That four to five days after planting is a
typical real nice time to harrow or if that crop is still an inch or so below the soil
if you can get out there and stir up that top inch or so of the soil. Typically a single pass if I have to do a
double pass after planting with the harrow I’ll take half the harrow with. That way I can follow one wheel of the tractor
will be in a row that I can see and then the other wheel will be where I’ve harrowed already
so basically you’ve got half the harrow where you’ve already harrowed and half the harrow
doing a new pass. You’ll do that all the way through the field
and typically the only reason I do a double pass is if the ground crusted to where I need
to get the ground broken up a little bit better. It may not look like you’re doing anything
but a lot of times it’s the weeds you can’t see that you need to be after at that time. Blind cultivation, or making light passes
prior to crop emergence, can be a good last chance to somewhat aggressively control weeds
in the entire field before growing crops limit the ability to control in-row weeds. You like to use the harrow because that’s
a good source of blind cultivation to get in-row weeds. So if you can use those blind cultivation
tools, I’ve found that that is really important to get grass in the row. If I see a weather system coming in that’s
going to bring rain I might harrow on the third day after just to be an extra two days
ahead you know. Then after the rain moves through, four days
after that you might want to be doing something, rotary hoe or whatever works for you I guess. Which implement to use for weed control just
after planting depends on many different factors. A spiked tooth harrow is generally more aggressive
than a rotary hoe but doesn’t handle residue as well. Farmers with more residue in their system
tend to favor rotary hoes over harrows and because rotary hoes are less aggressive they
can be used longer after crop emergence without damaging the corn or soybeans. But some farmers like Dean do use spike tooth
harrows after crop emergence. The corn can be spiking through the ground
as long as it’s not coming out of its whirl and leafing out you can harrow it. And just scratching that surface around a
little bit is all it takes to dry out, rough up that soil and let that top half inch or
inch of the soil dry out and therefore you can kill a lot of those weeds that are just
germinating simply by stirring up that top half inch. So this is what I use for a harrow. It’s a spike tooth harrow. It’s a five section, spike tooth harrow. It does have adjustments on it to where you
can adjust the pitch of the harrow teeth and kind of right now is kind of the adjustment
where I have it set to where I can harrow corn or soybeans. It may look like the spikes are probably going
to go further into the ground than what you think but by the time you get the harrow going
fast enough it’s going to lift itself out of the ground a little bit and that’s kind
of why I have tires on it to add a little more weight so it just doesn’t float across
the ground. If you set it at way too sharp of an angle
it will dig down and become an issue getting into your crop a little bit. You kind of want to set it so it’ll break
the ground up enough to where you’re happy with it I guess and it does a good job of
breaking up the ground and loosening up the weeds from the ground. Usually this is about the adjustment I make
it before I plant just to make sure I break up clumps and whatnot and get a smooth field
for the planter to run on. And after that you can adjust them down way
way down if you really so desire. Similar to harrows, many farmers like Paul
Mugge of Sutherland and Nelson Smith of Brighton use tine weeders. Dean says that newer tine weeders are effective
weed control machines but they can be out of the price range for many farmers. I know there’s other types on the market but
for people who are starting out or smaller farms you just can’t afford some of that stuff. It’d be nice to have but just not feasible. Dustin Farnsworth who farms near Adair in
southwest Iowa says his flex-tine harrow does a similar job to the newer tine weeders it’s
just less effective because the tines are shorter and there’s less of them meaning more
weeds can get through. But it’s also more affordable for someone
who’s just starting out. I like the idea of a tine harrow that I got
pretty cheap because it was older and a little worn out but it was still a tine harrow. And I like the idea of that because it came
a step closer to these new tine harrows like Einbock and some of these other European companies
are making that have narrow spacing of tines that catch everything and I like that idea
for blind cultivation but I can’t afford one so I figure the next best thing is to buy
a flex tine harrow that acts kind of the same way just not quite as good.

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