I suspect everyone's situation is different and requires different solutions. In my case in sub-tropical south AL, I have plants in the GH only in cold weather - it sits empty of plants from May - Oct. Also, the GH sits on a wooden deck 8' above the ground. I've never had a plant insect problem in the GH, but it does attract our delightful southern bugs such as fleas, bees, wasps, ants, roaches, beetles, ticks, mosquitoes.... I bomb the GH with a pyrethrin twice, spaced a week apart, in late September. That holds it until I clear it of plants the next spring.

Apparently there are not many that fumigate their GH's today - based on the lack of response to this post. It must have been more back in the 50's ? We did as much reading as possible on sulfur fumigation and decided to give it a try before planting any plants in our GH this year - and do some experimenting of our own.

One does have to be careful with open flames and I would not recommend it for small GH's because of the intense heat. We placed wood chips soaked in kerosene in a heavy duty deep metal pan then added sulfur chips (pearls) on top. The pan was sitting on a concrete paver and in an open area away from any combustibles. There were flames at first to ignite the sulfur. By the time the sulfur was burning the wood chips were consumed. We left the GH closed for 24 hours then aired it out. We don't know if this fumigation got rid of the red spiders and mildew - but it was worth a try - we will soon find out this spring. Sulfur has an irritating and suffocating affect on humans so one has to leave the GH immediately after lighting the sulfur. Do your own research - limited resources ourself - we are not suggesting that you fumigate the way we did - we would be interested in methods that work for you though.

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Now that the GH is fumigated - we plan to vaporize sulfur as needed in the GH to get rid of bugs and mildew on the plants throughout the GH season. We tested the method today before planting any seedlings in the GH. Are any of you using this or a similar vaporizer that could give us advice on usage and help us from making mistakes ?

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This post was edited by Hudson...WY on Thu, Mar 20, 14 at 15:45

My dad had a flower growing operation in central Indiana in the '30s-70s. When I worked in the greenhouses in the '40s and early '50s, before the day of synthetic fumigants, we did a lot of fumigation, along with spraying. The only fumigant name I remember is Nico-Fume, which I guess was nicotine based. It stunk up the place something awful. Another one left a less unpleasant sweetish, sort of almondish odor.

Billala - did the Nico-Fume work - not that I would want to try it if it smells so bad? The Sulfur didn't smell bad when I opened the GH this morning - it may have been that I didn't run the vaporizer long enough (I ran it for 5 hours) or our GH is too large for one vaporizer. The instruction say to run it 1-4 times a week depending on the bug activity (aphids, spider mites, mildew etc.) The sulfur apparently changes the PH on the plant leaves and the surface on everything else in the GH that eliminates the bugs, eggs & mildew. If the smell isn't any worse than it was this morning - I can live with that if it gets rid of the bugs/mildew!

The nicotine bombs had/have an Ld50 of 83. Pretty dangerous and I think idiots have died staying inside with their fumes. Its about 7 times stronger than diazanon. Have never heard of a pure sulfur burn. I like to jet spray plants when they get spidery, then if needed use a soap spray. Yellow pennzoil cans covered with petroleum jelly and preset around plants known to get whiteflies work very effectively.

Hudson - I guess the Nico-Fume worked. My Dad used it from the time I was old enough to be out there until I left home in the early '50s. I think it was for aphids, but I'm not sure. I probably remember it from when I was small because of how it was lit. You punched two holes in the can, put the can in a wire holder, then lit a sparkler (think Halloween), put the sparkler in one hole in the can, and voila, smoke started coming out both holes. You started in the far end of a house (two people did it in the end of two joined houses, three in the end of three joined houses etc.), then walked backwards to the front of the house waving the holder from side to side and staying ahead of the smoke wall. When you got to the front end you got out of there pronto and stayed out for some time - I think it was eight hours or so. He always did it at the end of the workday and left the place closed up until the next morning. I helped do it when I became old enough.

Sounds like a good option loveitgreen. The fumigation process may not be necessary for most GH's and certainly not applicable for small GH's - IMO. We did fumigate though - and now we vaporized with sulfur once a week for 3 hours during the night - on a timer. The vaporizer is also not for a small GH - our GH is just large enough for it to work with our 16' high ridge as the vaporizer does get hot and should be hung about 4' from the ridge and above the plants - to be effective.

We have had bugs and/or fungus mold every year since we built our GH - especially Aphids, Thrips and Red Spider Mites - constant battle! We are happy to report that we have not had one single bug or mold in our GH this year - NONE - GONE - we have done nothing except vaporize once a week for 3 hours - thats it - NO BUGS! There is more than one way to solve a problem!! So far - vaporizing with sulfur is working for us!

Now is a good time to Fumigate - before any seedlings are moved to the GH !!! We are fumigating with the Vaporizers this year. We have them on a timer and run them about 12 hrs a day for 3 days - then repeat again the next week for about 3 days.

The vaporizers worked great for us last year. We ran one vaporizer once a week at night time for 3 hours. This year we are running two - one vaporizer at each end of the GH. Our GH is 16' wide 28' long and 16' high. We feel we need two vaporizers to get better distribution of sulfur in the GH. We run them below the ceiling fans and above the plants - 3' from any combustable

The sulfur Vaporizer might not be right for your GH - so be sure to read up on it before you decide to use it -------- but it worked for us. No bugs last year period! No Spider Mites, no Aphids, no Thripes and no mold !!

Never fumigated and likely never will but there are loads of other steps to reduce insect and disease pressure. First, get rid of any remaining plant debris, especially live weeds, like chickweed, that thrive on the greenhouse floor margins since thrips and aphids will flourish on these live plants and infect new vegetable plants. Also keep nearby weeds removed if the greenhouse is open. Never allow last years plants to remain, especially ornamentals. Bacterial diseases will survive on wooden stakes so replace them if you have a problem with Bacterial Spot or Bacterial Speck. Dip all flats and plastic containers in a 200ppm bleach solution (1:25 chlorox) and then remove all other undipped pots from the greenhouse.

Others may have found the same thing that I have experienced with our GH - we don't have any remaining plant debris, no live weeds, no chickweed, last years plants never remain, no wooden stakes, we bleach our containers and pots - we never fumigated before - we tried many if not most of other options to control the pests and the strange thing is - every year it was a constant fight with mold and the bugs!

One does not have to fumigate or vaporize to control bugs - but it is an option! That is all I am saying - I am not trying to talk anyone into vaporizing - but it is an option for those that may be interested - but be sure to read up on vaporizing - good ventilation and other precautions are a must.

My GH - even though I can do better - is about as clean as they come - inside and out. I even power wash the GH in the fall - before I close the GH up for the season - as seen in this photo. Options and attempts to control bugs is not new to me - and our success is not very arguable - and YES - the plants you see in the photos grew and produced while vaporized with sulfur !!

Soil Nutrient

While sulfur is only needed in small amounts as a micronutrient to grow tomatoes, sandy soils can be deficient in sulfur. Sulfur helps form organic compounds that help impart flavor to tomatoes. Tomato plants with yellow-green lower leaves and elongated, woody stems may need more sulfur in the soil. The amount of additional sulfur needed is often fairly low, so a thin layer of compost of about one to two inches added to the soil may provide enough sulfur. Sulfur can also be found in many fertilizer mixes. Use about 1/2 cup per tomato plant. Work it into the soil when the tomatoes are small.

Fungicide and Insecticide

Powdery mildew spores can be carried on the wind to tomato plants late in the season. This fungus causes tomato plant leaves to develop yellow spots, and can eventually kill the leaves. Sulfur can be sprayed on the plants to reduce infestation. Another tomato pest, russet mites, can be controlled with sulfur, but it may take several applications. Sulfur can also be used to prevent an infestation.

Applying Sulfur

Sulfur can be applied as a dust or as a wettable powder. When applying as a dust, use a hand-cranked dust applicator in dry, windless weather. Coat the leaves and stems of the tomato plant lightly. The wettable powder form of sulfur is stirred into water. However, it doesn't dissolve. It is applied with a specially designed sprayer.

Cautions

Sulfur can damage tomato plants when the weather is hot, and should not be used if temperatures climb above 90 degrees Fahrenheit. If squash and melons are planted near tomatoes, do not use sulfur, as it can injure these plants. While sulfur is less toxic than many chemical pesticides, it is best not to get it on your skin or in your eyes as it can irritate them. Avoid use on a windy day to keep from inhaling the sulfur or it spreading to other areas. Wear a long-sleeved shirt, long pants, eye protection and plastic gloves when applying sulfur. Wash tomatoes thoroughly before eating them to remove any sulfur residue.

Sulfur can be used in the soil or on the tomato plant to help develop tasty tomatoes.

Growing your own juicy, red tomatoes is relatively easy. But when leaves yellow or the fruit fails to mature, sulfur can help, both in the soil and dusted on leaves as a fungicide and insecticide. Sulfur and copper are the only fungicides allowed for use on certified organic produce

http://homeguides.sfgate.com/information-putting-sulfur-tomato-plants-29024.html

I am bumping this thread because I found this article at the http: above. I want to share the article because we have had the same results as described in this article in our GH with the use of sulfur. We use sulfur as both a dust and vapor (during the night only). Maybe sulfur is why our tomatoes have such a great taste!!? What are your thoughts and experiences?

Sulfur is not normally used as a foliar application on greenhouse tomatoes because of the fact that more than one application per year can have an adverse effect on the parasites of whitefly. (Univ. of Florida IFAS)

Hudson, I congratulate you on finding a solution that works well for you! Your greenhouse and tomato plants always look so near perfection, so I was just a little happy that you also have to deal with aphids and mildew like the rest of us! ;-)

You've put in lots of research before making all your greenhouse related decisions, so thanks for sharing your sulfur findings.

Thanks ddsack! The sulfur vapor system has worked awesome for us. We do have to deal with aphids and mildew but I have to be honest - since we vaporize with sulfur we have not seen either of them for two years now! I know, it surprised me too. We keep looking for aphids because they were such a problem before we started with sulfur vapor!!