Scarleta- I've had a lot of trouble with aphids in my lighted shelves indoors where I start seedlings. It's all because I foolishly brought some plants back in from outside. Those aphids really get around. Is there some time you can have the greenhouse empty to get rid of them and then never bring any plant inside that has been sitting outside to reinfest them? Perhaps it's harder with a greenhouse since it's outdoors and perhaps the aphids can find ways to get in. There must be some way to control them like Safer's Insecticidal soap or Neem. I also tried soapy water without much success and damaged a few seedlings.

Have you tried the real heat-lovers in your greenhouse like okra, watermelons, and cantaloupes? It's not hot enough here to grow them in the ground.

You might find lots of good ideas on the greenhouse and structures forum, /strucs. Here is a link discussing peppers. I don't have greenhouse experience to help you. Is yours heated in winter? Do you use it to start seedlings for outdoors, and make cuttings in winter? That's what I do with my lighted shelves but I don't have sufficient light or space to grow tomatoes or peppers to fruiting stage in winter, which would be nice. My peppers don't do well in our cold soil so I have them and eggplants in pots on my deck and they are fruiting and have no signs of aphids.

Here is a link that might be useful: greenhouse forum on peppers

Another link for you-

Here is a link that might be useful: aphid search

Thanks Hemnancy: You got it right .I do start all my seedling indoors and when its time to harden them off I take them out for few hours increasing time out daily and put them back into the greenhouse at night.I don't have a cold frame and that is precisely how I bring them inside.
Okra sounds really good because I do like it a lot.I just have no experience with okra.I grow in pots only in my greenhous. Can okra be planted in pots? If so what size? How tall does it get? Tomatoes do well there, but get too tall My green house is mostly used for starting out seeds.I would like to plant something for the summer that is easy, won't get infested with aphids.Thanks..

Scarleta- I harden off tomatoes starting in April on a concrete east-facing covered porch. and don't bring them back in (except I did bring some plants back in once for bad weather that caused the aphid infestation, will not do that again). I grow the okra in pots along with eggplant and peppers, and I get a few even in a one gallon pot. I suppose the bigger the pot the bigger the plant could get and the more fruit it could have. Mine have not gotten bigger than maybe 3' and don't have many fruits, but I have a variety this year that seems to be setting well. It's strange, there don't seem to be any blossoms. I will have to try moving them up to bigger pots and see if they do better.

The melons could be grown up some support instead of sprawling and not take up much room. I haven't tried growing them in pots but it could work.

Thanks again.I plant tomatoes in March/April so I start hardening them off in May/June.I have to gradually introduce them to sun as they are hardening off because my green house does not get any sun only grow lights.So I have to keep moving them back into a green house.I burned them so badly few years ago that they never really recovered.One hour of sunshine to start with and gradually increase.So I keep taking them out and bringing them back.Some of my plants never need to be hardened off ( if they stay in a greenhouse all season).I know that doing it this way I bring all the aphids and the rest into the greenhouse.what I really need is a proper cold frame or a small greenhouse that I can place in the sun and harden them off there.If I can find a plant that does not get aphids I can keep doing it this way and then have some plants staying all season in my greenhouse.Its a big job to carry the tomatoes, peppers, eggplants each day in and out of the greenhouse.The sun can really do more damage to the little plant never introduced to sunlight than cold or even rain..Any suggestions? I grow organically ..Thanks

When I had a greenhouse, I sprayed weekly with horticultural oil mixed with baking soda for combined aphid/scale/mildew control. Worked pretty well. But it will kill larval ladybugs and lacewings which are your primary biological controls of aphids.

All plants get bugs. It's not reasonable to expect to avoid them entirely. Plants exist to feed bugs after all! Or at any rate, bugs have evolved to take every advantage of feeding on plants.

Thanks Reg: I thought that perhaps there is something that I could grow and the aphids would not like it.Looks like I have been dreaming......

The aphids never bothered my basil.:-)

Thanks Hemnancy once more.That is very interesting.Never thought of it .My basil is outside and growing very happily and indeed nothing seems to bother it.I don't need that much basil only about 6 plants.I do have more room in my greenhouse, so I am considering to just use it for starting seeds.( my gh has no natural light)That way I won't have problems and won't keep the lights on.On the other hand I would grow something that I use lots of .Othervise I won't bother keeping it just for 6 plants.Thanks if you have any other ideas please do let me know...HOw about okra? I like okra a lot.Never planted it so I have no idea if aphids or other creatures get attracted to it? Please share if you have any points.That way I would keep both okra and basil.in my green house.thanks