Re: whether to start indoors or out
Posted: Sun Apr 03, 2022 8:40 pm
Hi, a few things to mention---in no particular order:
as well as clones, there are counterfeit copies of the Univent on Amazon. I had email discussions with the manufacturer in Denmark in an attempt to find a preferred US vendor. They seemed genuinely surprised when they saw all the look-alikes on Amazon, they thanked me profusely and said they were taking immediate steps to remedy the situation. Other than that, English was a second language and I never did get a preferred vendor list. Instead, I paid a little more and bought it from Johnny's. The peace of mind is priceless
since I put the seedlings out around March 25, I only have a couple of weeks, typically, to keep an eye out for extreme cold. The temps should moderate as we get into April. We did have a few nights---maybe three, where the temp hit 20, 21 and 23. The hot bed/ cold frame (not sure what to call it) bottomed out around 54---which is about what my cellar was every night. All of the thirty-something nights, it has maintained a nice 63-65 degrees. The heater has a lot of reserve capacity but would require more playing with the settings. When the heater was too high, it kept the Univent open---despite it being 35 outside, it was 77 inside. I dropped it down little by little until a 30 degree night was mid-sixties inside and then the following 50 degree overcast day, it stayed below 75---which is where the Univent is set to open. The Univent opening temp can be adjusted up or down but I was trying to find the spot where the heater could maintain 60 at night and 70 during the day. There is an optional thermostat for keeping an even tighter control on the heater but I didn't spring for it.
putting a double layer of polyethylene on the cover would have bought me a few degrees of further cold temp protection, allegedly at the expense of some light transmission. I opted for the extra light.
yes, I do have a generator and it feeds the entire house as well as the circuit in the garden. Should a worse case scenario arise---frigid cold in the single digits or the generator runs out of propane, I guess I could always throw a blanket over it for the night. Between the warm ground and the 5 gallon pail and 1" thick foam insulation, a blanket over the top would probably get me through??? I will never forget the April 1 snowstorm many years ago but by a couple of days later, most of it was melted by the seasonable weather that returned. By putting the plants out on March 25, my window of vulnerability is not that large and I would still have several weeks to start again should the need arise
I placed the heater at the rear in the center of the cold frame. I didn't want to put it directly under the Univent where it might affect it. I placed an old computer fan facing it to disperse the heat, prevent cold spots and strengthen the plants. This worked fine until I tried to rearrange the inside a bit. I moved the 5 gal pail almost into the corner and faced the fan at it, thinking the air would uniformly wend its way around the sides of the square structure. It was the weirdest thing. The temperature probe on the trays with the pots in them said it was 63 degrees---but the vent was now open several inches??? WT? It turned out to be a weird way the heated air bounced around and it then hit the Univent, causing it to open---yet several inches below the vent, where the temperature probe was, it was 63. I put everything back the way it was and will try to remember to never do that again
the cold frame is roughly 40 cubic feet. The heater for a plastic pail was supposed to be capable of maintaining the pail at 60+ degrees on a 35 degree night---with nothing to spare. I opted for the larger 550 watt heater. There was a website somewhere that let you plug in the space the pail/barrel will be in, the ambient temperature and the liquid that will be in the pail and tells you how many watts you need to maintain a certain temperature. I used 40 cu. ft., water at 60 degrees with 35 as the ambient temperature. There are weather sites that will give historic temperatures---highs, lows and averages. Should you opt for a metal pail, they come with several different interior coatings. Basically, the ones that come bare with a spritz of rustproofing are only intended to prevent rust while in the warehouse---not real rustproofing as one might surmise. The different epoxy coatings for the interior are determined by the material that will be in the pail. In my case, it was water which called for the "red" epoxy coating
the cold frame structure was originally a fence for a bed for bush beans. The rabbits loved them so I built a light weight fence that popped in as 4 separate sides and popped out again when you were through. I used black 1/4" hardware cloth (screening) to keep the rabbits out. I decided to keep this setup and just put foam board inside and make a hinged top. The back of the foam board was bright white with blue lettering (which would have been facing out) so I sandwiched in some black landscape cloth for looks. The cold frame doesn't have a sloped roof but it seems to be just fine for my intended purpose and the time of year. I put an ever so slight pitch to the bed (pried up one end with a shovel), hoping it would facilitate rain runoff but it wasn't sufficient. I have decided that I would rather have the small puddles (the vent opens the lid and it drains off quickly) than to look at something I did that was cock-eyed
working with the foam board was challenging. In order to cut it cleanly, with no jagged edges or little white pebbles falling out, I used a straightedge and a 3-4" paint scraper. At first, using a belt grinder, I put a sharp edge on the paint scraper and with several successive passes against the straightedge, I got fairly clean cuts. Then I tried heating the paint scraper with a propane torch until it was quite hot. One pass along the straightedge and the results were perfect. Any place I had to make a cutout---say for the mounting bracket for the Univent---I didn't want square inside corners, which break. I wanted rounded inside corners. I used a pair of Channel Locks and a copper 3/4 pipe coupling and heated that with the torch. When pressed in to the corner, it melted a perfect 3/4" radius. Word of warning---the fumes are beyond nasty so this should be done outdoors!
in order to hold the lid open, I opted for simple boards on the outside of the cold frame. Initially, I wanted them inside---out of sight---but decided, sooner or later, something would go wrong and the lid would come crashing down and the lid stay would poke a hole in the polyethylene.
I made all of the joints in the wood and the insulation as tight as I could. Then, after several days of rain, the wood started to swell up and move around. The joint between the lid and the sides now had a slight gap. I stapled on some felt weatherstripping to the top of the sides. Then the wood shrank and the lid now couldn't close as tightly as before because the weatherstripping near the hinges prevented a clean seal on the front of the cold frame. I transferred the weatherstripping to the lid stays and it seemed to solve all of the wood movement/leak problems.
I would be happy to post some pictures. A cursory search here as well as a Google search left me in the dark. I don't have any cloud storage that I use. Directions to the how-to page?
as well as clones, there are counterfeit copies of the Univent on Amazon. I had email discussions with the manufacturer in Denmark in an attempt to find a preferred US vendor. They seemed genuinely surprised when they saw all the look-alikes on Amazon, they thanked me profusely and said they were taking immediate steps to remedy the situation. Other than that, English was a second language and I never did get a preferred vendor list. Instead, I paid a little more and bought it from Johnny's. The peace of mind is priceless
since I put the seedlings out around March 25, I only have a couple of weeks, typically, to keep an eye out for extreme cold. The temps should moderate as we get into April. We did have a few nights---maybe three, where the temp hit 20, 21 and 23. The hot bed/ cold frame (not sure what to call it) bottomed out around 54---which is about what my cellar was every night. All of the thirty-something nights, it has maintained a nice 63-65 degrees. The heater has a lot of reserve capacity but would require more playing with the settings. When the heater was too high, it kept the Univent open---despite it being 35 outside, it was 77 inside. I dropped it down little by little until a 30 degree night was mid-sixties inside and then the following 50 degree overcast day, it stayed below 75---which is where the Univent is set to open. The Univent opening temp can be adjusted up or down but I was trying to find the spot where the heater could maintain 60 at night and 70 during the day. There is an optional thermostat for keeping an even tighter control on the heater but I didn't spring for it.
putting a double layer of polyethylene on the cover would have bought me a few degrees of further cold temp protection, allegedly at the expense of some light transmission. I opted for the extra light.
yes, I do have a generator and it feeds the entire house as well as the circuit in the garden. Should a worse case scenario arise---frigid cold in the single digits or the generator runs out of propane, I guess I could always throw a blanket over it for the night. Between the warm ground and the 5 gallon pail and 1" thick foam insulation, a blanket over the top would probably get me through??? I will never forget the April 1 snowstorm many years ago but by a couple of days later, most of it was melted by the seasonable weather that returned. By putting the plants out on March 25, my window of vulnerability is not that large and I would still have several weeks to start again should the need arise
I placed the heater at the rear in the center of the cold frame. I didn't want to put it directly under the Univent where it might affect it. I placed an old computer fan facing it to disperse the heat, prevent cold spots and strengthen the plants. This worked fine until I tried to rearrange the inside a bit. I moved the 5 gal pail almost into the corner and faced the fan at it, thinking the air would uniformly wend its way around the sides of the square structure. It was the weirdest thing. The temperature probe on the trays with the pots in them said it was 63 degrees---but the vent was now open several inches??? WT? It turned out to be a weird way the heated air bounced around and it then hit the Univent, causing it to open---yet several inches below the vent, where the temperature probe was, it was 63. I put everything back the way it was and will try to remember to never do that again
the cold frame is roughly 40 cubic feet. The heater for a plastic pail was supposed to be capable of maintaining the pail at 60+ degrees on a 35 degree night---with nothing to spare. I opted for the larger 550 watt heater. There was a website somewhere that let you plug in the space the pail/barrel will be in, the ambient temperature and the liquid that will be in the pail and tells you how many watts you need to maintain a certain temperature. I used 40 cu. ft., water at 60 degrees with 35 as the ambient temperature. There are weather sites that will give historic temperatures---highs, lows and averages. Should you opt for a metal pail, they come with several different interior coatings. Basically, the ones that come bare with a spritz of rustproofing are only intended to prevent rust while in the warehouse---not real rustproofing as one might surmise. The different epoxy coatings for the interior are determined by the material that will be in the pail. In my case, it was water which called for the "red" epoxy coating
the cold frame structure was originally a fence for a bed for bush beans. The rabbits loved them so I built a light weight fence that popped in as 4 separate sides and popped out again when you were through. I used black 1/4" hardware cloth (screening) to keep the rabbits out. I decided to keep this setup and just put foam board inside and make a hinged top. The back of the foam board was bright white with blue lettering (which would have been facing out) so I sandwiched in some black landscape cloth for looks. The cold frame doesn't have a sloped roof but it seems to be just fine for my intended purpose and the time of year. I put an ever so slight pitch to the bed (pried up one end with a shovel), hoping it would facilitate rain runoff but it wasn't sufficient. I have decided that I would rather have the small puddles (the vent opens the lid and it drains off quickly) than to look at something I did that was cock-eyed
working with the foam board was challenging. In order to cut it cleanly, with no jagged edges or little white pebbles falling out, I used a straightedge and a 3-4" paint scraper. At first, using a belt grinder, I put a sharp edge on the paint scraper and with several successive passes against the straightedge, I got fairly clean cuts. Then I tried heating the paint scraper with a propane torch until it was quite hot. One pass along the straightedge and the results were perfect. Any place I had to make a cutout---say for the mounting bracket for the Univent---I didn't want square inside corners, which break. I wanted rounded inside corners. I used a pair of Channel Locks and a copper 3/4 pipe coupling and heated that with the torch. When pressed in to the corner, it melted a perfect 3/4" radius. Word of warning---the fumes are beyond nasty so this should be done outdoors!
in order to hold the lid open, I opted for simple boards on the outside of the cold frame. Initially, I wanted them inside---out of sight---but decided, sooner or later, something would go wrong and the lid would come crashing down and the lid stay would poke a hole in the polyethylene.
I made all of the joints in the wood and the insulation as tight as I could. Then, after several days of rain, the wood started to swell up and move around. The joint between the lid and the sides now had a slight gap. I stapled on some felt weatherstripping to the top of the sides. Then the wood shrank and the lid now couldn't close as tightly as before because the weatherstripping near the hinges prevented a clean seal on the front of the cold frame. I transferred the weatherstripping to the lid stays and it seemed to solve all of the wood movement/leak problems.
I would be happy to post some pictures. A cursory search here as well as a Google search left me in the dark. I don't have any cloud storage that I use. Directions to the how-to page?