Citrus tree

Question

I have a lime tree, Mandarin and lemon tree that I brought indoors about a month ago due to cold weather. I had them covered by plant fabric and they were OK but I was worried about the light. The are now in my hot tub room (plenty humid) under a grow light for 10h a day. My lime tree is losing leaves and fruit by about 50% so far. I would say 50 limes now to 25. I water once a week until it comes out the bottom. The only thing I noticed was spider website and I do remember seeing spiders outdoors but haven’t indoors. I’ll send you pics to pick your brain. The lime is on right, then mandarin and lemon on the left. Thank you

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Answer 1

Webs on plants are often made by spider mites, so check your plants for these tiny arachnids. You can learn about them here:
https://www.gardeningknowhow.com/plant-problems/pests/insects/spider-mite-treatment.htm
http://ipm.ucanr.edu/PMG/C107/m107bpmites.html
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7405.html

I think the more important issue for your plants is the light level, though. Unfortunately, it's very difficult to give plants as much light indoors as they get outdoors, so most plants will lose some leaves and/or fruit when they're brought indoors. A sunny window combined with a grow light or two is usually the best option. If you don't have a sunny window, you could use a couple of grow lights and use some mylar sheets or other reflective material to increase the light that reaches the plants, as described here:
http://www.ctahr.hawaii.edu/kobayashik/supplemental.html