Does it make sense to try a low tunnel now?

[OneDahlia]

I was out playing in the garden yesterday since it was 65 degrees here in Northern Virginia (!!), and started thinking ... since we haven't really had any winter yet this year and the soil isn't very cold, I'm tempted to make a low tunnel and plant some lettuce, spinach and peas. This would be my first attempt at 'undercover gardening.' Is a low tunnel covered with plastic enough protection to even try this?

We're supposed to have highs of 50 or above through Thursday and 40s after that, with lows around 30. Average highs are more like the low 40s and lows in the mid-20s, and of course it can get colder than that. We should be getting some snow someday, lol. And we might get all our winter at once in February or March ...

Basically, when we're actually supposed to be planting early spring crops, the uncovered garden beds will probably finally be freezing cold and waterlogged.

So what do you think? Since I've never done this before, I really don't know if it would work and what issues I might encounter.

[saltmarsh]

Hi OneDahlia,

I need a little more information.

Does the sunrise or does the earthturn?

If you think the sunrises, then no you shouldn't.

If you think the earthturns, then you probably shouldn't.

If you don't care one way or the other, go for it; but try to have fun during the vagaries of winter. Claud

[OneDahlia]

Hmm, I take that as a no.

I know some people manage to keep cold-season veggies growing all winter in my region (even if it's slow growth, just to get a good start in the spring). But I don't know if a low tunnel is enough to manage that. I guess that's what I should have asked. Suppose I'd probably need something more substantial though.

[saltmarsh]

I'm just trying to have a little fun and eat ripe tomatoes too. Without a heat source and venting, anything that isn't cold hardy will probably freeze or burn up. I was suprised how high and quickly heat builds up with the plastic down. As an example, when the sun is shining at 10:30 in the morning the temp inside goes to 101 degrees when it's 42 degrees outside. At 11:30 when the outside temp is 52 degrees the inside temp will go to 134 degrees (it would have gotten hotter but I chickened out and raised the plastic).

Without a heat source, the temp inside will be 3 - 5 degrees warmer than the outside temp. I'm using a 1250 watt heater and it seems to be adequate for this area. The hot house is 4' wide x 20' long x 7' high.
A vent fan at the top pulls outside air inside when the temp reaches 75 degrees, which keeps the inside temp at 78 degrees when the sun shines.

The heater kicks in when the temp inside drops below 70 degrees and will keep the temp inside at 55 degrees when the outside temp is 22 degrees (the coldest it's gotten so far).
Today's pictures.

[OneDahlia]

Nice! What do you have growing, and how do they taste in the winter?

3-5 degrees won't cut it, so I guess I'll wait. I'm not ready for anything more than a low tunnel yet. Thank you!

Will just have to get my gardening fix by digging a couple more beds today.

[RobinB]

I have one of these: http://www.gardenharvestsupply.com/P...ouse-p3547.htm
The price has gone up a lot, I paid $80 about 6 months ago. It is un-insulated, so I added some bubble wrap (don't laugh, it works). Before next spring, I'll probably cut some real insulation of some kind, but I like the fact that light still gets in from the sides.

I'm not trying to grow tomatoes, Claud is right, unless you have an external heat source, you can't grow summer veggies. BUT, you can grow winter veggies. I've got turnips, broccoli raab, carrots, kohlrabi, chard, lettuces, arugula, spinach, mizuna and we did have bok choy but we ate it all a few weeks ago. When it gets below 25 or so, I add a Garden Quilt in there (Gardener's Supply Co.). We bought 50' of this a few years back and it's cut up into various sizes. It works great and still lets light through. So far, it's been 13 degrees this season and with the garden quilt everything did just fine.

We haven't had our winter yet either. It sounds like our weather is almost the same as yours, although after a week or so with lows just at freezing, now our lows are creeping back down to the 20s. Last night was 23.

I say, go for it! You might want to set it up a few days in advance and warm the soil up a bit, and/or germinate your veggies inside and plant them inside your greenhouse. My stuff was started by direct seeding, but that was in October. Everything will grow slower than you think. Since some things have been eaten I'm germinating more lettuces inside to plant outside. Before the winter is over (if it ever comes) I'll probably lose it all... or not. We usually have a week or two of single digit low temps before it is over. It's only 3' square, but before this I had never tried a winter crop. It works!!!

We got a new camera and I just took some photos of my little project. As soon as I figure out how to get the photos OFF the camera, I'll post a few if you'd like.

[OneDahlia]

Cool! It's good to hear that's working for you in similar temperatures. The price is still not that bad when you factor in free shipping for something that size, and I see that they have coupons sometimes. I like that it looks very portable too.

I'd love to see pictures.

[saltmarsh]

OneDahlia,

I'm growing eggplant, tomatoes, bell pepper, cayenne pepper, and onions.

The cayenne is planted next to the heater and they seem to love it.

The eggplant and bell peppers are the farthest from the heater (it gets about 10 degrees cooler on that end than the end the heater is on) and while the bell peppers are producing good tasting and normal size fruit, the eggplants each have about 6 fruit 2 - 3 inches long which haven't increased in size for the last 3 weeks. I think it's just a little too cool for them.

The tomatoes suffered from an attack of early blight, but I removed the diseased leaves and treated them with a multi-purpose fungicide and they're making a crop. No difference in taste, but slower to ripen and a little less productive than regular season tomatoes.

A few surprises:

I haven't watered in over a month. Apparently it's like a large terrarium with moisture condensing on the plastic and running down to the ground where the roots take up all they need from the edge of the frame and repeating.

Several of the tomato plants are touching the plastic and even though it's been down to 22 degrees twice and below 25 several times none of the leaves show any signs of frost damage.

This photo shows the tomatoes with early blight before being treated back in November. Claud

[POAJoan]

Robin, just sent you a pm as I am also in Reno. But we have been a heck of a lot colder than you! It has been 14-16 at night all last week, but we're also at 5500 feet. Good to see another Renoite on tomatoville. Joan

[OneDahlia]

Claud, that sounds very successful overall. Thank you for sharing! Maybe next fall I can try something like that. Enjoy!

So yesterday (the day after I started this), it snowed all day, lol. OK, OK, it really is winter. Even though it's supposed to get up to 52 today ...

[saltmarsh]

OneDahlia,

I'm happy enough with it for a first try. Probably the most important thing I learned from this is to treat the ground, mulch, plants, and the inside of the plastic with a multi-purpose Fungicide at the beginning. If I had done this one thing, I believe it would have been even more sucessful (but I've never used a fungicide before this).

Anyway, I bought another piece of plastic and if I can get a fairly warm dry day I'm going to install another set of hoops on top of the existing roof to give me an inch of air space between the plastic covers in preparation for Feburary's weather.

The plastic has been rolled up (except on the north side) for the last 4 days, but comes back down tomorrow afternoon as the forcast calls for temps back down in the 20's a couple of days from now. Enjoy your snow and also not having to worry with plants out in it. Claud

[RobinB]

Claud,
Fungicide, what specifically? Is there a product that you have tried? I remember last year having some problems with my maters when I removed the Wall O'Waters. I pruned some of the leaves so that there was better airflow and it seemed to do the trick. It's so dry around here (usually humidity is in the single digits in the summer) that fungus isn't usually a problem, but inside the WOWs they don't breathe all that well. Some years, I have gotten some powdery mildewey stuff on my squash and melons at the end of the season though.

[saltmarsh]

Robin,

That's been my experience in the past, pulling the lower leaves has worked for me as well, but growing plants in a closed environment is totally different from growing in the open. Once the Early Blight started, it spread like wildfire inside the closed space.

The product I used is Spectracide Immunox Multi-Purpose Fungicide spray concentrate purchased from Home Depot. Other stores in your area may carry it. The active ingredient is Myclobutanil 1.55% other ingredients 98.45%

I followed label directions and applied 1 ounce per gallon and applied with a 3 gallon hand sprayer. The label said it would not wash off if allowed to dry and I was fortunate to have a sunny day to apply it. First I removed the leaves showing the worst infection then sprayed tops and underside of leaves and plants, mulch, and the inside surface of the plastic. This stopped it dead in it's tracks. Leaves spotted with infection won't regrow the damaged area, but the disease won't spread. It's been almost 2 months and no sign of recurrence, the one application seems to have worked for me, but I'm still watching for signs of a recurrence. Claud

[janezee]

Originally Posted by OneDahlia

I was out playing in the garden yesterday since it was 65 degrees here in Northern Virginia (!!), and started thinking ... since we haven't really had any winter yet this year and the soil isn't very cold, I'm tempted to make a low tunnel and plant some lettuce, spinach and peas. This would be my first attempt at 'undercover gardening.' Is a low tunnel covered with plastic enough protection to even try this?
So what do you think? Since I've never done this before, I really don't know if it would work and what issues I might encounter.

I'm a little warmer than you, but winter hasn't really started here in the PNW either.
I have double low covers on one of my 4x8 raised beds, and single cover on the 4x4. I planted onions, leeks, spinach, broccoli, cabbage, beets, and more lettuce on Sunday when it was 55, and tonight it will be 30. Lettuce I started in October is growing, though extremely slowly.
Old fashioned Christmas lights, with the screw-in bulbs keep it from freezing, and in a week or two, I'll put them in to start things growing if it drops into the 30's in the daytime again.

Eliot Coleman gardens all year in Maine with no added heat. Look up his books in the library. You'll want one, I'll bet!
Winter Harvest
Four Season Gardening

janezee

[OneDahlia]

Thanks, Janezee! I'll look up those books. I figure that the biggest benefit probably isn't the harvest over the winter, but a faster start in the spring. And the fun of having something to fuss over outside.

Good luck with the things you planted! I'd love to hear later about how they do.