If you got the space, why not try? Rocks have been discussed also.

Depends on what you're growing. Small starts, just make a cover for them in the gh. Put Christmas lights under there and it'll be nice and toasty.

With just a simple cover over one bed, it's 19 outside right now at 11pm, 25 in the gh proper, but almost 35 under the cover. Using nothing besides what little heat the soil gained during the day.

-Ed

I'm going to try rectangular storage containers. Bigger containers should work better, because they'll release the stored heat over a longer period of time.

I'll report how they work over the winter.

Stuart

I am trying this aswell, i won't have half as many bottles as she does but it just might work.
Consultant now that you mentionit she has a big plastic barrel in there to. So that would prob help.

I thought I read somewhere that many smaller bottles works best. More surface area to collect and release heat. I know my 55 gal drum will still have a cold spot inthe middle bottom after many heated days. The small bottles make sense as long as they don't release heat so fast as to freeze your plants out at 4AM. Anyone know for sure?

The problem with small bottles is that they release their heat too fast. By 4 AM, they probably would have no more heat to release. Maybe the best solution is a combination of large and small containers.

Yeah a combonation might work. Another thing that might be helpful is painting the water containers black so that they absorb more heat from the light. I haven't finished building my GH yet, but ive read about this stuff. I wouldnt try it for all winter. I would always have some kind of back-up heater for emergencies. This also depends on your zone and all of course and how much sun you get, etc. The GH size makes a difference too. I hope to try some of this technique in my first winter ever in my new GH!! I'll think I'll use a combo of the water container technique and some kind of heater. The water containers are also nice because they keep the humidy up alittle if you need it.

I'm going to use an electric heater in mine. I'm just hoping the water with help keep heating costs done a little. Increasing the thermal masss will help the greenhouse in the summer too. I'm shooting for about 175-200 gallons of water in my 6' X 8' HFGH.

From what I've read the water storage containers have to have a lid on them or the heat will release too fast. So actually they will not be creating extra humidity. Unless you keep your greenhouse really hot humidity will not be a problem in the winter time. There is usually plently due to condensation.

Im thinking about wind power any thoughts?

Last winter I used 60 black painted 2-ltr soda bottles filled with water along with a programmable thermostat and an oscillating portable heater with fan. I did not maintain a growing temperature at night, just a no freeze temp. The thermostat was set at 40 degrees.

I was delighted with the results. The bottles were placed on their sides under the racks I used for the plants and some plants were even put on two bottles. I was amazed to find that those plants that were on top of the bottles never lost leaves or went down hill and maintained vigor and even had new growth. Those not, expectedly did not do so well. I am already in the process of saving more bottles for next year. I plan to cover the entire floor with them (except for a walkway).

X

This is my first post however I have read many post. I have a HFGH bought last Febuary. With pic from this forum I was able to put it together . That said I have a question. I accuired a swimming pool insulation cover. I would like your opion on putting it on . Will it be to heavy when we get our usual ice storms here (Texas)? Also I have read many post about electric heat . What about propane heat. Robby

Steel drums would allow you to store more water in a given volume/space than having a bunch of small containers taking up room, and the metal surface would allow for more efficient heat transfer than plastic. Painting them black helps, too. And you can use two of them as supports for a work surface.

Kudzu..I am hoping to find a couple of metal 30 gal containers for just that purpose !

Robby...After alot of research - for me- the small electric heaters should provide the most heat for the money for my HFGH. They are cheaper to run than propane here. Kerosene for a backup in case of no electric for me. :)

http://freespace.virgin.net/m.eckert/incorporating_pcm's_in_building_materials.htm

covers a bunch of potential materials for phase change thermal regulation. Easy to obtain materials include hexadecane (diesel), parafin waxes, calcium chloride hydrate and some of the larger alcohols.

Fatty acids were claimed to be good, but I worry about the potential to attract pests.

In response to those replying to this original post that have mentioned painting thier containers black to help absorb heat, I found this to be a fallacy. I tried a little experiment last summer, I took a clear 5 gallon container and an identical black painted container, filled them with water and set them out in the sun for most of the day. the clear container became MUCH warmer by end of the day than the black one had.

RE:Wind Power... I have considered the same option with my greenhouse, and after much research, I have determined that for the average hobbist greenhouse and many smaller professional operations, the cost per Kw/h will actually be HIGHER than electrical or hydrocarbon based heat sources. the best estimates I could come up with with all best possible situations was a 15-20 year to break even with a wind system.

With a small Ghouse, you are still probably best off with the traditional electric, NG or LP systems

Interesting results, Virgo (another analytical Virgo here, 090348). I tried the same thing and found the black-painted containers to be significantly warmer than the clear ones. Perhaps we need to consider other factors?

Virgo the nice thing about wind powered electricity is that it does not use non renewable resources. It isn't always about the money.

Another idea would be to grow straw or other biofuel in your greenhouse over summer, and burn them when it gets cold. I don't know whether this can breakeven in the colder zones, but it is really a far more compelling solution than either fossil (i.e. mains electricity/hydrocarbon heaters) or indirect renewables such as wind.

What would the burning of the straw/other biofuel do to the environment? I think that would be harder on it than electricity or a gas heater. Especially as efficient as the heaters are today.

Ultra enthusiastic types could use body heat.

Sleep in the greenhouse :-)

No GH gasses beyond the usual.

SH

weebus, what do you mean? are you refering to CO2 (clearly neutral), or particulates (no different to burning any other biofuel such as wood or cord - you need a suitable stove).

Exactly. Wood and cord are inefficient and dirty to burn. Here in Washington there are many days that it is illegal to burn wood unless it is your only source of heat in your home, which is a minority

A good thing to remember is......

In a greenhouse every available space you can find should be stuffed full with rocks, water bottles, trash cans full of water, old chevvy engines, in fact anything you can lay your hands on that is heavy.

Fill all the space (wasted space) under your benches with whatever you can that will not be harmed by high humidity or damaged by high/low temperatures or give off toxic fumes that may harm your plants.

As to burning things for heat.... Wood, corn, straw or waste veggie oil is good. (CO2 neutral)

Propane, natural gas, coal and using electricity is bad.

Wind power is GREAT for providing the electricity for the "command and control" functions of a green greenhouse. (water pumps, fans, vent openers, monitoring systems and alarms) For the generation of heat you need to "burn"

Going back to the start...

""Ok I visited a lady's GH and she has NO electrical heating devices. She uses water bottles!!! She fills them with water and the sun heats them up and they retain the heat till evening when it cools off, and then they keep it warm by letting the heat off.
She even has some plants in it now and they been have sprouted for about a week."" That was Apr 28, 05 in New Brunswick Canada I assume.

Took a look at their weather, and I am not at all surprised that with a large thermal mass you can beat the frost in mid April there.

cactusfreak,
""From what I've read the water storage containers have to have a lid on them or the heat will release too fast.""

Yep, evaporation is causing that effect. You are loosing heat from your barrel by the water evaporating during the day and being blown out by the fans. If you have a cover on the barrel then the water still evaporates, but much slower as under the cover it is 100% humid.

As to burning things for heat.... Wood, corn, straw or waste veggie oil is good. (CO2 neutral)

Propane, natural gas, coal and using electricity is bad.

Do you just dream this stuff up?

If you haven't noticed, plants need CO2. Here in the PNW our electricity is produced by hydro. The dams are there, with waterspilling over. No need to waste electricity, but it is FAR cleaner to use than wood.

Even if your electricity is being produced by hydro, there is basically no more capacity for it worldwide, and electricity is by far the most valuable form of energy. Far better to use low-grade energy such as biofuel for heating and use electricity for things like control. If you advocate using electricity for heaing you may encourage the construction of more fossil fueled power generation plants.

Biofuel depends on what you are using to cover biofuel. If it is wood, I strongly disagree. I live in the PNW of the US and I can tell you the horrors of over harvest of timber and your throat and eyes burning on overcast days.
There is muxh more capacity for electricity without fossil fueled (coal) generation plants. Wind energy and wave energy are prime examples and they do not pollute our environment like most biofuels

Off topic...I saw this cool thing (in Scientific American, I think) about these enormous snakes that will be tethered in the ocean, that use wave action to power generators in the "joints" of the snake for electricity. SB

Ya know, I just spent over an hour writing a "Treaties" on the pros nad cons of all the possible heating systems before I realized I was in danger of going off topic and needed to use the K.I.S.S. rule.

If you are going to have a small hobbiest greenhouse (No more than maybe 8x12ish) and aren't going to try to raise any tropicals that cannot tolerate under 55Deg F, go electric. Otherwise Go gas. Natural gass if it is available, otherwise propane. Do NOT use kerosene heaters, bad for the plants. All those other systems discussed are NOT cost effective for small ghouses.

The real trick is to be effecient in retaining that heat and take as much advantage of solar gain as possible. Use as much thermal mass as you can fit into your ghouse ( preffereably water in your choice of container.. I like 35 gallon rubbermade trash cans that double as bench supports, but anything that holds water works).

Insulate the dickens out of the north wall and possibly even the lower third of the east and west walls.

Make sure your ghouse is tight(ie no air infiltration except for heater venting)

Use a poolcover over your greenhouse, just have to remember to pull it back at dawn then forward again before dusk. You can occsionally forget to pull it back in the moning but you MUST have your ghouse covered at night.

The link below is to my favorite agricultural supply house, FarmTek. It is a wonderful place to get ideas .

Here is a link that might be useful: farmtek

virgo91967,

You are getting a "feel" for this. If the goal is plant survival on a bad day or night the rules are vastly different to keeping an optimum environment.

The lower the zone number the more interest there is in preventing plant death than providing the ideal growth environment.

""Insulate the dickens out of the north wall and possibly even the lower third of the east and west walls.""

North wall on mine is a wall (and so is half the north roof) and the lower third of the east, west and south side is a wall too)

As to what you said about ""All those other systems discussed are NOT cost effective for small ghouses."" then I tend to disagree. If you are already using a large thermal mass of water then an injection of a 140,000 BTU boost by burning a gallon of WVO in an hour every couple of days can really help.

"Use a poolcover over your greenhouse, just have to remember to pull it back at dawn then forward again before dusk."

Nobody I know here on GW with a solar pool cover retracts the cover in the morning. Are you kidding? The thing weighs like 50# and it took me three hours just to get it on in the first place. Plus adjustments every 2-3 days for the first three weeks everytime it got windy.

BTW, when it's windy, the pool cover is not worth s--t. Two dozen clips, bungee cords, 200# of rope and it just flaps in the breeze. I'm seriously considering another method for next year. But I'm off topic, here, so I'll find a pool cover thread and post there. SB

I am using the water bottle system...I have several bottles that I filled wth salt water NaCl...I probally have about 30 bottles total and 3 wiith NaCl...I am growing orange, lemon trees...they are small and fragile...they are showing good growth...and all leaves are very healthy....it has been below 40 at night in the GH...so tropicals can survive below 50...and do good...I have a smalll fig tree...bought it late and didnt want to put it in the grown at that early stage due to winter damage...I have 7 figs on it and it is developing new leaves like crazy..
I have 6 tomatoe plants which I am have started to produce tomatoes...not many but even during the summer fiirst production is always slow....I have a peppercinno plant in therer which has also started to flower....along with 2 hybiscus the troppical kind which hasnt shown any cold stress...Keep in mind I have no heat and the outside temps has been in the 20's at times and GH temp has been below 30...none of the water bottles has froze..whiich I was surprised...I do get ice on the inner walls...but it hasnt bothered the plants...as long as they dont touch the wall....from what I can tell the soil hasnt froze either....and some contaniers arent really that big...I have some 2 inch container...I do not completely understand this...but it is cool..I have come to the conclusion that there seems to be no need for heat in a small GH..as long as it is fillled with plants...soil bags....anything that will hold heat....ohh yeah the salt water contaiiners stay warmer longer...I need to get a thermometer probe to do further research on this issue...but it is very cool...I think atleast..

Steve

Has anyone tried black clothing dye in clear plastic water bottles? It only takes a few drops and is a lot easier than painting individual bottles. I think some paints appplied to the outer surface of the bottles may act as an insulator and actually prevent the water from reaching maximum temps.

For dying the water, I've wondered about using pond dyes - they're vegetable based and should they spill might be less likely to create a permanent stain.

i've been reading the forums. i'm new to this, but i've learned alot. thanks great info!! my question is this can you heat a 20'x 36' greenhouse with a wood burning stove? pros and cons ? and how? the stove would be inside the greenhouse not piped in??

I have a black pond dye and they warn that it can stain, and it does. Mine is a powdered type from Lilypons, but I would suspect that any dye could stain.

Sorry, going back slightly to what was being discussed earlier: has anyone thought about geothermal energy? They say in some websites that it is ideal for greeenhouses. It basically includes pumping heat either from the earth or from another area of high heat, to your house/greenhouse. I don't know the exact pricing of it but i imagine it's quite an expensive set up, however, you could power both your greenhouse and your home for half the price of regular central heating.

Also, there is a new glasshouse opening here in 'sunny' England which is to be dome shaped and built into the side of an old quarry (how original ;) ). What IS original about it is that it is heated by manure! A large hole (really really large) is drilled down the quary until it reaches the level of the base of the glasshouse. It is piped under the glasshouse floor and then filled with manure/any agricultural waste. The heat produced in the decomposition process heats the whole structure.

Anyone fancy making a new compost pile nextto their greenhouse?

However, my idea at the moment is to use a boiler powered by calor gas canisters with an underfloor copper pipe network. I worked it out at around £10 ($17) per month for a 12 x 12 to be kept at 15C in my zone. So not too bad, probably less that i would be spending on two or three fan heaters. However, it may work out at slightly less than that because i hadn't accouted for the raised black water pond that will be in there, along with double glazing on two of the walls, twinwall polycarb roof, bubblewrap and raised stone beds (no pots).

Happy heating,

Hen