Hoop House Issue...How to Solve Please!

staf74 wrote:

Odd Duck, love the set-up. I hope this does not sound too dumb but are those kinda little white towers around your garden some kind of watering device? I see the hoses look connected but could not quite work it out? Also, love the frames to support trellised plants. They look custom built. Did you weld them? IMPRESSIVE.

The white tubes with the inverted plastic pots are the worm tubes, pretty much as Josh described in his thread. They are not connected to the watering system, the hose just happens to lay next to them. The hoses are just hooked to sprinklers. I haven't yet set up a proper drip watering system, that's on my list, though!

The frames are just bent 1/2" electrical conduit. They are connected at the top to the long piece with end to end connectors. The side pieces are drilled at the meeting point, then connected with bolts, split-type lock washers, and nuts. The galvanizing makes welding conduit a bugger, so we had to use alternate options.

I don't know what kind of pain would be safe to use. I garden organically so I'm hesitant to put anything... unnatural... on my soil.

jerzyjen wrote:It's my understanding that painting the bottles black will absorb the sun even better, however I didn't have the paint and didn't feel like spending the money. Probably only a few bucks and might do it later, just didn't want to spend the additional money for the gas for a special trip to get it.

I don't know how well my setup will work if it gets down in the low 20s or lower, but hopefully I won't have to find out.

I did my little side-experiment for you today. I put one black jug in the sun, left one in the HH, and left a clear one in the HH, too. I didn't put a clear one out in the sun, though. But, after only one day, the results were pretty clear.

Our air temps got up to 58F today. The clear jug only got to 63F. The black jug out in the sun got to 62F. And, the black jug in the HH got to 67F! Clearly black is better. But, only using a clear one is better than putting a painted one out in the sun....but not by much.

As for the day, I got to 58/83F today. I only partially opened the HH, though, and the sun was out ALL day for a change. Once the sun angle was lost, the HH came back down to air temps really quick, as I was outside with the kids while it happened. I mean within 20 minutes the HH went from 70-ish to 55F. I don't know when the 83 happened because every time I checked (about 6 different times), my thermometer showed low 70s at best.

I put the 2nd layer on tonight since we are supposed to drop to 31F. I don't want to take the chance with my new transplants of a night the weathermen miss by 2 degrees. However, I used the 3.5mm plastic instead of the 6mm. I folded it over 4 times, not on purpose, but I actually think it will be a great thing because it will have air pockets all in the folded up plastic (when I say folded, I don't mean neatly folded like bed sheets). That insulation will be interesting to see tomorrow. I bet I don't get down to 40F inside the hoops with that plastic combining with the heating from the day.

Have a good night, all. I'll report in the morning.

I used to use a camp shower bag that was designed to heat the water by laying the water filled bag in the sun, so your shower water was passively warmed. This plastic bag had a clear side and a black side and the idea was to lay the bag clear side UP. The idea was the heat energy went into/through the water even before getting to the black part, which absorbed even more heat to transfer to the water.

Maybe you can try painting just one side of a jug, setting it so the paint is on the north side so the light/heat goes into the jug then hits the black side and gives up it's last bit of heat energy. Do you have one more jug and a bit more paint to experiment with?

Do I have more than one jug to dedicate to the experiment? Don't make me laugh....

(Not that you know this but...) I have three small children guzzling milk like a baby whale. I produce two milk jugs per week. In a year, I could likely climb up the STL Arch on my milk jugs.

OK...just joking around with you. I know you didn't know all that.

But, yes, I can put one out and paint just the back and re-run the experiment. For some people, it would be hard to accumulate as many milk jugs as I have in such a short period of time. But, Sunny D, orange juice, 2 Liter bottles of soda, etc, all work, too.

However, I cut the bottoms off my 2 Liters now and use the top as a potential cloche and the bottom as a vermiculite starting tray......




Last night was 33/37. Not quite the differential I was hoping for, but certainly safe enough.

My laughing in my post was because pretty much every one can come up with another milk jug, but even more so on whether you would want to run yet another experiment. I knew you would, I just thought it funny that now we're suggesting experiments to order!

I added two more bottles yesterday and we had a really sunny afternoon. Last night I went out and put a blanket on top (since my HH is so small one blanket was sufficient). The low outside was 27, inside the HH the lowest was 40. That works for me! I vented this morning, but I just hope that I don't have the opposite problem and it gets way too hot today while I'm at work.

I have 6 baby lettuces and I planted 6 spinach seeds, I worry about the lettuce getting fried if it gets too hot.

Odd Duck, I find that funny, too. It would be fun to get paid to do scientific experiments. Oh wait, people do. Hmmm, maybe I chose the wrong major in college.

Jen (for some reason I had a Coyote Ugly flashback and wanted to just call you Jerzey), that is a great differential. Now, you don't have to worry until temps go into the low 20s on sunny days. Once you know what it does on cloudy days, you can adjust your frost date to match....likely with confidence. You may acheive Miami status before I do...lol.

I figured I would just copy/paste the quick update I put in the blog today since I would say the same thing here....


Just a quick update. Not a lot has changed, but…

Hoops still hold well at 4-5F above outside air temps. I haven’t used the 2nd cover in awhile, and still haven’t dropped below freezing. Last night was 34/38F.

The veggies inside seem ok. The broccoli and cauliflower seem to be thriving. The lettuces are experiencing some apparent shock; however, I have other transplants ready to take their places if need be. No peas have sprouted, nor carrots from the direct planting I did 10 days ago….but that is to be expected (and I dont know the extent of the digging damage I took from a squirrel…or my dog.) I do have a spinach plant poking up from the direct seeding, so that’s exciting.

I will be transplanting carrots and more spinach this afternoon. These sprouted from the vermiculite cups method I used a week ago. And, the others from this attempt are already in the garden. More on that below.

I planted a tray of lettuces yesterday in hopes of transplanting them next weekend.

The method I am using is pretty simple. I was impressed enough with the vermiculite, I bought some brownie trays. I poked holes in the bottoms, and laid some paper towels over the holes. I filled them with an inch or so of vermiculite and watered it down. Then, in rows marked by popsicle sticks, I planted 5-8 seeds of each lettuce variety. I sprinkled dry vermiculite over the top and set aside for a few days. I should see something in a few days. When their baby leaves open fully, I will pull them out of the vermiculite and pop them directly into the garden.

Pics coming soon.

Quick update......another frost last night.

7am this morning.

Outside Air Temperature - 28.8
Under the first plastic cover - 33.4
Under the floating row cover - 38.7

Nice differential. No thermal mass used. Was hoping to use the plastic bottles but simply not needed. Potential for another light frost Thursday night.

Then snipped about 20 big juicy spinach leaves for a snack today and set off for work.

That is great news! I am watching what you do closely as it seems your weather is pretty close to what we have here in the foothills of California as far as frost is concerned.

Yummyyy....spinach leaves! I can hardly wait! That is one of my favorite things to do...eat my spinach as I'm out in the garden. Come to think of it, not much made it into the house for a salad last year!

What kind of thermometer do you use? Where did you get it? That is something we need to pick up....

Thanks again for sharing and keep posting!
Nancy

Staf, you have me doubting my jugs now. If you got that kind of differential under a naked 2nd row cover, my jugs may not be providing much. Either way, I feel confident we can both survive frosts from what we've learned.

VeggieO, I can't speak for everyone, but my max/min thermometer was bought at Walmart for $6.

I, personally, have no sign of frost in the near future. So, I have only used my 2nd row once in the past week. And, I won't be using it this week as of today's forecasts going forward.

Veggie O's,

A pic of my thermom is on page 4 of this thread. I bought it at Lowes a few years ago. The sensor measuring the "OUT" temperature is on a wire which just means that I can place it somewhere and get a dual reading as the thermometer also has another sensor actually attached to it. They are gravitating now towards wireless thermometers for dual readings and so mine is already outdated but works fine.

BBG, I want to make sure I understand you when you mention the "naked 2nd row cover" as I've been known to confuse both readers AND myself. The beds were protected last night by two layers. The main plastic layer AND the row cover. I had two thermoms. One reading the outside air temp. The other "dual" thermom reading inside the hoop and the sensor attached by wire tucked UNDER the row. Thats where my readings come from. Also, as a tidbit for lurkers late to the thread, my row cover is actually a big piece of plastic folded many times and so I'm probably getting some extra insulation that way from dead air trapped in the folds. Its about 4 inches thick when loosely folded.

Anyhow, I have not tried the jugs thingy yet as I'm having great success with what I have. I'm actually surprised at my differential. A steady 9 or 10 degrees every time I've used BOTH row and hoop cover. However, I would not be discouraged BBG. I've learned a lot from your experience. Thermal mass clearly is a well documented process that works but I would probably guess that thermal mass needs more "MASS" than one gallon jugs to be truly effective. Again, that is just a guess.

By "naked 2nd row," I meant no jugs underneath. So, we are on the same page.

I like the therms with wired sensors for this purpose, and they are cheaper than wireless models, too. Win/win.

My plastic "row cover" is folded multiple times, too. And, I believe that traps the heat as you are proving.

I am going to test the second row cover without the jugs, but maybe not until next year. I don't think it's going to get cold enough now, for one. But, also, I am not going to risk the smaller plants I have going now just for the sake of an experiment...lol. Those "how cold will it get" experiments are best tested without plants inside, imo.

And, my point about the jugs being in doubt now is because you are proving a very similar differential without them. That 2nd row may be doing all the work. And, if that's the case, saving and painting milk jugs is really a waste of time for this garden.....therefore, inefficient. And, we all know SFG is about max-efficiency. Why do something just for the sake tradition?

Kind of like the old joke about the newlywed cooking her first Thanksgiving dinner? She wonders why they cut the ends off the ham. She asks mom.....mom tells her to ask gramma....gramma tells her to ask great-gramma......great-gramma finally says, "I don't know why they do that these days. In my day, we HAD to cut the ends off the ham because we didn't have a big enough pan to fit the whole thing." buh-dum-bum-pssh.

Point is: Don't just do something because it is "believed" to work. Test it yourself. You may cut out a bunch of unnecessary work.

Last night we were surprised by the temps. Things caught the weathermen off guard....of course.

The scenario: Days upon days of cloudy, rainy weather. This allowed hardly any heating inside the hoops. I think my highest temp inside the HH the past four days was 50F. That ain't gonna heat the water jugs up much. Yesterday was supposed to be about 45F for a high.....but it never happened. We touched 39 briefly. The clouds were so socked in that there was no sun getting through to provide much heat. The wind was a bit blustery and that likely whisked away anything the soils absorbed. So, when the clouds disappeared at midnight-ish, we sank like a rock. The radiational cooling effect was tremendous. I, personally, wondered why the meteorologists didn't adjust their numbers based on the fact they missed the daytime high so badly, but they didn't. No winds to speak of and crystal clear skies mean temps plummet. We were forecast to hit 29 or 30, but went all the way down to 26F. And, my HH suffered.

I woke up this morning to sunshine and got outside as quickly as I could to get the 2nd layer off and let some sun hit the plants. Good news.....no frost inside the hoops. But, the trade off was my temps finally went below freezing. Down to 30 underneath the 2nd layer of covers. I don't think that did any damamge, and it wasn't at 30 for long I'm sure. But, nonetheless, I went under 32 for the first time since putting plants in there a couple weeks ago.

Obviously, I am not going to beat Mother Nature forever. I am only trying to thwart her more feeble attempts to keep me inside. I can survive sudden changes down to 25, but can't sustain temps in the mid-20s for prolonged periods. And, lack of sunshine is a real killer, too. If I don't get some sun a couple times per week, my proverbial ship will sink even faster when the temps take a nose dive.

I also had the 3.5mm plastic on as my 2nd layer last night, too. I will switch back to the 6mm if temps are forecast to go below 30 again. ...or, if I know they might regardless of what the guys on tv say.

So far, so good, though. The plants underneath are still doing well. They are obviously growing slowly, but they are fine. We'll see what last night did to them soon.

Just thought I'd let you all know that despite our best efforts to learn the details of the HH, we are not completely weatherproof over here.....yet. Hee hee.