At first glance, I scoffed at the whole idea. On closer inspection, the solar greenhouse may warrant some consideration--keeping in mind a few of the limitations of solar. For one, solar panels are only about 15% efficient at converting the sun's energy to electricity. And that only gets it to DC power, which then has to be converted (with losses) to AC power to use in the home. So you wouldn't want the panels to shade your plants during the winter. That being said, the UK is so far north (and thus the sun's winter angle so low), that this may work. You will have to look long and hard at how the finances work out however. Solar panels are not extremely efficient (as stated earlier), and the UK with its overcast weather and northern latitude has some pretty depressing numbers for solar potential! However, if the utility costs are are high, it might price out to be an advantage to you. If you want help with any of the analysis, I am willing. I took a course in photovoltaic systems design last semester, and am pretty quick with numbers.

nathanhurst I'm not going to get into an electronics lesson with you, but you (with all due respect) are complete wrong on how amperage, wattage and voltage work. Real quick. Using your idea of connecting the panels to get 120V is not correct. Two problems with your scenario 1) the heaters we are talking about are 120V AC. Your method only provided DC current. While the elements can handle DC, the fan cannot. There may also be other electronics that are running off of a power supply thatÂs designed for AC. You need an inverter to change DC to AC. While there does exist inverters that will convert, say, 120DC to 120AC, this is not widely used in the Americas. 2) Parallel or SeriesÂ. That is the question. What you first need to understand is that in order to increase AMPERAGE, you need to connect the panels in PARALLEL. To make things simple, letÂs say that a single panel is 15 watts (thatÂs approx. 1 amp at 12V)  (which each panel is in the kit aboveÂ. 3 panels make 45 watts, which is approx. 3 amps at 12Volts). And also, letÂs use small numbers just to get the point across here. 1 panel producing 12V = 15 watts = 1 amp To product 10 amps at 12V, you connect 10 panels together in a parallel manner (positive to positive, negative to negative). Now, if you take those 10 panels and connect them in series (positive from 1 panel to negative on the other panel and repeat for each panel you end up with 1 positive and 1 negative when done). That would make 120V DC, BUT, it would be 120V at 1 amp only. To be clear: - Connecting panels in parallel increases AMPERAGE (watts) but the VOLTAGE stays the same. - Connecting panels in series increases VOLTAGE but the AMPS (watts) stay the same. So using your idea, in order to product 1,500 watts (which is approx. 12.5AMPS) you would need: 10 panels in series = 120V at 1 AMP (letÂs call this 1 set). To make the MINIMUM 12.5 amps (we are not including startup amperage or other necessary things to take into account when configuring a system)Â. you need to connect 13 "sets" (rounded off) of the above connected in parallel. ThatÂs 130 panels (individual panels). AND THEN, that would ONLY product the required amperage ONLY in direct, full sun (we havenÂt calculated for dimmer light levels). You still need an inverter here, which of course, also costs in amperage loss. Hopefully, you now understand how this works. Ok ok, so IÂve been a technician for over 30 years! LOL I just hope that I explained it well enough. I admit, itÂs difficult for me to put my knowledge into short words. LOL But like IÂve said before, itÂs better to use a water heating system for a greenhouse rather than solar electric panels.

Kimmsr, I agree that we should all try to minimize our use of nonrenewable resources in the garden. Perhaps a better approach for me would be to make sure that the llama pellets are well moistened and then to cover them completely with something like grass clippings to retain the moisture. I too have had good success using cardboard to kill off lawn for new garden beds. I used to strip all the sod off but I finally learned that that was way too much work and that the organic material from the decomposing turf will add to the soil quality of the new bed. I do have a number of pieces of scrap glass around so I may try using those instead of clear plastic to increase soil temperature and retain moisture. You know, I think what would really help me most is to have an easy method for crushing llama pellets into a powder. Any suggestions for that?

Thanks for your response, lazygardens. I should have been more clear, and I know that, so I apologize. I will be building this greenhouse, actually I should call it a very large hoop house. During the summertime I will be using a specially designed shade cloth that blocks-out the suns harmful rays. In addition to that I want to install a very large evaporative cooler that I already have. What I'm looking to do is to have solar power to power the evaporative cooler to cut down on electrical expenses, which around here, keep going up and up to beyond reasonable. During the winter I will remove the shade cloth and put on a specially designed clear plastic. I used this shade cloth for my tomatoes one year and it worked very well, even without an evaporative cooler. I hope this makes it a little clearer as to what I'm trying to do. BTW - I'm sure many of you are aware of the company where I get my shade cloth from, but in case you're not I recommend them highly. I have no connection to them other than being a very satisfied customer. The link is below... Greg Southern Nevada Here is a link that might be useful: Shade Cloth - Greenhouse Supplies