Nope...don't mind questions one little bit. My first question back to you concerns your greenhouse covering. Polycarb, single or double pane glass, insulated and/or treated glass? If you have single pane glass, I believe that will allow more harmful UV light and heat thru. You may require some sort of shade cloth or white washing the roof glass. What sort of venting do you have?

All of this is going to contribute hugely to your heat buildup. I have double-paned, insulated and treated glass. We've had days pushing 100 degrees outside and my greenhouse rarely got above the outside temp. A lot of times it was below. This was due to not only my venting options but since I am keeping the humidity very high, my fogger was going off quite a bit. I've also got the fogger tied in with temperatures. If the temp goes past a set point, the fogger kicks on. Every time it goes off, it lowers the temp a good bit.

Because of my glass, I don't have any fear of scorching a plant unless it is a specimen requiring more shade than others. Go for the cheapest and easiest options first...unless you can afford to go all out with this.

As for your lychee? Don't feel alone. Mine looks like hell and I can't figure it out at all.

Thanks a lot for the good suggestion.

I guess what you said a while ago is absolutely right, you need a professional greenhouse to grow these tropicals in the north.

My greenhouse is actually a solarium that is attached to the house. It made of triple panel glass, the roof can isolate most of the UV and only let 30% solar heat in. The side glass can let 50% solar heat in. But unfortunately I don't have a roof vent, just a side electrical vent. I open all three windows plus a sliding door, with the vent on and celing fan running, but it still rises to 40 degrees. I guess I have to invest on some sliders. I have ceramic floor and a knee wall, so I can't use fogger. I guess I am just kidding myself a bit here.

My lychee is still unconscious now, I don't know how long it's going to take for the poor thing to wake up.

Don't give up. I grew all my stuff in a spare bedroom for 3 years before I built my greenhouse. If your glass is triple pane, I doubt enough UV is making its way thru to scorch the plants. Have you fertilised lately? Done anything out of the ordinary? How's the soil PH? Too small or too large a container? Water? It doesn't take much of any one thing to throw container growing out of kilter. These trees in southern Florida experience high temps and a scorching sun during the summer and they do just fine. I would look for another source of your troubles besides heat and UV. You could install a large fan to exhaust heat out a door or something. And to tell you the truth...my lychee looked a million times better when it was in a container. It has struggled ever since I planted it in the ground. I'm at a loss for its condition.

Nothing has been done recently except that I just moved the plants from outside into this room. Then we had about two weeks cold weather, but the sunroom is kind of warm, so it's loaded with new growth, then all of a sudden, the weather becomes hot, the room temperature rises to 40 degrees, then it was just fried. I think the temperature rises too fast for the lychee tree to adapt.

The big fan is a good idea, the air exchange is the key.

Thanks a lot.

Yellowthumb, I hope you don't mind if I chime in...I also have a couple of Lychees in my GH. It is one of the toughest tropical fruit trees to grow in the north.

I agree that once acclimated, they should be able to handle plenty of heat. My GH regularly hits 100F in mid July and my Lychees don't seem to have a problem. But new growth on a Lychee is unusually sensitive to excessive wind or underwatering. They are also very sensitive to overfertilization.

You can try to optimize all the cultural factors, and the tree still won't grow like it is supposed to. Funny OJ should mention container versus ground bed...I just dug up my 'Brewster' from it's former home in the ground and put it back into a container.

SB

SB...glad you chimed in. You jumped the gun on me! I've been contemplating the exact same thing for a few weeks now. The PH is spot on. Organics, the mulch has broken down wonderfully, earthworms, I've stopped any fertilization, great drainage, increased the watering. It's in ideal soil... maybe too good? I even covered it in a screen to block some of the sun since it is definitely stressed...grasping at straws here. I'll see how the next flush turns out.

My main problem is that green, healthy looking leaves will just fall at the slightest touch or shake. Just doesn't make any sense. What once was a tree you couldn't see thru is now threadbare! Everything else I put in the ground is growing like mad. If it doesn't turn around soon, I'll probably put it back into the container. Let us know how your Brewster does.

check planting depth, (I am sure this is unlikely with those responding thus far) Also, a chance of a big empty spot in root zone. I use so called chemical ferts and have no problems with my lychees. They are in ground of course, and outdoors, so maybe this is useless info.

good luck

Alan

In my experience, lychees are very sensitive to any major changes in their environment. My 'Sweetheart' lychee looked like it was about to die for about four months after I put it into the ground; I was getting frequent leaf drops even after new growth flushes. Eventually the tree acclimated and grew at an impressive rate thereafter - it's three years old now and almost ten feet tall with a ten foot spread. If everything else seems like its in order, then you're probably just dealing with a tree that's adjusting to its new life in the ground.

I hope that's all it is but it's been in the ground now for nearly eight months. Thanks