Cold frames vs. quick hoops
planting lettuce, onions, and spinach yesterday, I pondered the pros
and cons of quick
hoops versus cold frames. I'm not going to have
any side by side comparisons this year, but I have started noticing
that each system works a bit differently. Here are the main
factors to consider when choosing whether to build a quick hoop or a
- Light penetration ---
This is where I suspect that quick hoops win. Cold frames have
wooden walls that shade a relatively large area on the south side of
the bed, and in early spring I've noticed that lettuce just won't
germinate in that cold spot. Quick hoops don't create any shady
areas, and so far I've seen no cold spots that restrict germination.
- Heat capture --- I have
no data here, but my gut says that the lower profile of cold frames
would hold the day's heat closer to the plants. However, Eliot
Coleman's experiments suggest that light penetration is more important
than heat capture when growing cold weather crops, so quick hoops'
lower ability to capture heat might not matter.
- Water penetration ---
Here quick hoops lose. The flat top of cold frames lets water
pool on the row cover fabric just long enough to drip down through and
water your bed, but water mostly runs off the quick hoop. I was
surprised to see dry spots inside our quick hoops this week despite
inches of rain in as many days.
- Snow load --- The same
structural features that make water slide off quick hoops makes snow
slide off as well, so I suspect quick hoops would stand up much better
snow conditions than cold frames do.
- Wind --- The higher
profile of quick hoops catches wind much more than our cold frames
do. We haven't had any more major trouble since I added the rebar
to the sides, but we also don't live in a very windy climate. If
you live in a treeless area, you might be better off with cold frames.
- Ease of opening --- This
is a toss-up, but I think that cold frames win. It takes me about
five minutes to carefully unroll the rebar and take the row cover
fabric off the quick hoops, although if I just want to peek in I can
simply untie one end and stick my head under the fabric. My cold
frames are usually much
easier to get into. That said, I suspect that we can come up with
a more accessible quick hoop as we play around with the design.
- Cost --- If you have old
lumber lying around like we do, cold frames are a big winner since they
only cost as much as the fabric and screws. On the other hand, if
you're buying the materials new, I estimate that our quick hoop costs
29 cents per square foot (if you use the cheap PVC rather than the
hot/cold version) versus 64 cents per square foot for a cold frame (if
you use untreated 2X10s).
- Longevity of fabric ---
After the initial construction, the only regular cost for either system
is replacing tattered row cover fabric. I've noticed that the
tautness of the quick hoop fabric makes it very
easy to punch your fingers through, and the rebar tries to snag and
tear holes as well. However, our animals don't think quick hoops
look like a fun thing to jump on, which is the fastest way to lose row
cover fabric, so we might actually get a bit more longevity out of our
quick hoop fabric than out of our cold frames.
- Modularity --- Our raised
beds aren't all the same width or length, so I've found it difficult to
move cold frames from bed to bed. With my rotten, salvaged
lumber, cold frames also tend to fall apart when I move them.
Quick hoops are much more modular since you can just drive in your
rebar stakes at the edges of the bed and cover irregularly shaped beds,
using the same raw materials in different years to protect beds with
somewhat different dimensions.
- Speed of contstruction
--- Once we knew what we were doing, it took about two hours of my time
and half an hour of Mark's time to make a 23 foot long quick
hoop. Cold frames require two people for more of the process, but
probably take about the same number of man-hours.
- Ease of storage --- Quick
hoops win big here. During the summer when I don't need our cold
frames, they're leaning up against a fence or wall, which creates
a weedy spot that's hard to mow around. Quick hoops disassemble
into a few long poles and a bit of fabric, so they'll be easier to fit
- Aesthetics --- Our cold
frames are pretty enough, but there's just something striking about the
domed quick hoops that tempts me out into the garden.
- Worm collection --- I don't know if
this is a positive or a negative, but our quick hoop seems to collect
earthworms in the rolled up fabric on the edges. I pulled this
handful of worms out as I opened up the quick hoop Tuesday, and the
chickens were very appreciative.
Overall, my gut feeling
is that quick hoops are the winner, although
I'd love to figure out a way to make them easier to get into. I'm
pondering making long, skinny sandbags out of old dogfood sacks that
can be laid along the entire edge of the structure. Stay tuned
for more details!
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