The Tropical Fruit Forum

From what I've seen citrus are very tolerant of hard pruning. Meaning when cut back or frozen back they reliably send out new growth from large wood. If pruned very hard most northerners will think you killed the tree. The tree won't mind and it will be a chance to clean up scale and the like. I'd go after pest issues as hard as you can while it's easy.

The spiders may be spider mites. It's hard to tell from the picture. If they are two spotted spider mites a good hand lens can allow you to see the two spots for an ID. They can be controlled with horticultural oil. But don't apply within 3 weeks of a sulfur application. Usually they aren't an issue outdoors. A high pressure water spray can help with control.

A natural gas CO2 generator will put out a tiny bit of heat. But that's not it's purpose. It generates CO2 to increase plant growth. The greenhouse needs to be closed up so as to contain the added CO2 inside the GH. In summer when sunny, a GH will need ventilation. Thus, any added CO2 would quickly be lost to the outside.

It's really only useful when the GH is closed in winter. Under those conditions I've increased CO2 to 800-1000 ppm just using a compost pile. I could not tell any difference in growth but that would be difficult to notice.

I've also found that CO2 builds up at night in a tightly closed GH. That's off gassing from soil, pot media, and plant respiration. And CO2 doesn't fall as quickly as I expected during the following day. I had difficulty dropping it much below 400 ppm, and outside level.

You can drain the perched water out of a pot by setting it on a towel or other material that absorbs water. That would help dry out the mix with no root disturbance.

It might also help to warm up the pots. Take them inside. Cold and wet is worse than warm and wet for some species.

I can spot a nitrogen deficiency in many plants by the color of the leaves. Leaves in N deficient plants are lighter green in color than with adequate N. Older leaves can senesce early as nitrogen is cycled into the newer growth.

Cool soils can cause similar symptoms on plants like banana that like warm soil.

That doesn't sound like sprinkler damage to me. With all the rain and humidity you have two sprinkler events a week shouldn't be an issue. But that's just my intuition. Good luck..!!

One can't be sure. But that kink in the left shoot above the fork could be a graft union. Bud grafts often look like that.

Asking the seller might solve the issue.

That looks like salt burn. Perhaps from the hurricane that you had not too long ago. Salt still in the soil from that storm. The usual cure would be to leach the salt out with fresh water.

It doesn't look too bad to me. My thought is maybe it's getting too much shade. And perhaps it's suffering from root competition from those nearby trees. More water and fertilizer might help. Removing some of the competition might help.

Then again those trees may be farther way than they appear.

That's very nice looking. Those should grow great with no competition from weeds.

What are the temperatures and rainfall in your area? And what are the main pests and diseases?

Sulfur probably won't stain your tile. What I'd use is a wettable powder. Sulfur dust is also effective against certain pests. They should wash right off.

Sulfur is very effective against fig bud mites but I'm not sure how it will do against spider mites. It's also widely used against powdery mildew. Probably not so good for scale or mealybugs. Oil would be better against those. I may end up alternating sulfur and oil. But don't apply together or they'll burn the leaves. I'd allow 4 weeks between sulfur and oil.

I had full control of everything in my greenhouse this summer with about 8 sprays of the same thing that Millet uses, ultra pure hort oil.

Next year I'm going to try wettable sulfur because I want to have control of powdery mildew if it shows up on grapes or mango.

My main pests are: spider mites, fig bud mite, and scale. I didn't see a single spider mite even though they've been an issue every year for 20 yrs. Scale shows up once in a while, none this year. Fig bud mites were my biggest issue this year. I saw mealy bugs once but cut out infected foliage and sprayed the hort oil. None since. One little patch of aphids.