Responded on your duplicate thread on Vegetable Forum.

I would pluck off the oldest, leaves. They'll probably die anyway, and the plant will probably grow faster without them, considering the light changes. It'll reduce the amount of light the plant gets.

The plant won't grow faster without the oldest leaves. As long as they are green they are photosynthesising. They won't reduce the amount the light the plant gets and they increase the plant's ability to use that light. They'll fall of their own accord when the plant no longer needs them.

@floral Although photosynthesizing can help plants grow, for plants in transplant shock, I think too much photosynthesis is part of the problem. It takes time for plants to drop leaves (if they do it at all). Roots help to supply water for photosynthesis. Plants need water for photosynthesis. More photosynthesize than they have water for seems it would dehydrate the plant. I'm guessing this is why for plants in transplant shock, the leaves turn thin and both the leaves and stems wilt (because they use the water they have available and are having a hard time getting more, due to the damaged or insufficient roots). The more leaves a plant has, the more water it needs (I have tested this in containers), and in my experience, plants don't just turn off their leaves from functioning at a moment's notice when it would be helpful—otherwise, the most common kind of transplant shock, IMO, would not occur (and a moment's notice is sometimes what they need, believe it or not; twenty seconds of strong sun can kill a leafy plant with sufficiently damaged roots). If the roots aren't sufficient for the amount of foliage and sun, similar symptoms as transplant shock should occur as if the roots are damaged. Plants with root rot could have the same symptoms. Plants with too much nitrogen and too little potassium may have similar symptoms, for a similar reason. Giving plants extra potassium is one way to reduce transplant shock (I have tried this a number of times). It helps plants to absorb water. It also helps the roots.

Note that people advise you to remove a number of leaves when you take cuttings. They might have plenty of reasons, but cuttings don't have any roots; I've discovered that they need time without too much light to adapt to the situation (otherwise, they'll wither and die; cut a piece of a leafy plant off and lay it in direct sun, and cut another off and lay it in the shade; you'll see that the one in the sun withers quickly and the one in the shade might look healthy for a really long time). If they have less leaves, they'll have less light. If they're in a low light environment, or are adaptable, you probably don't need to worry about removing leaves of cuttings. There seems to be more to adapting to the light than just having the roots needed. The plants seem to be in shock, and after a certain length of time without being damaged by / exposed to sun, they don't seem bothered as much if they're put in more light (as long as it's not too much), even if the roots aren't grown.

What I'm saying is, the plants are still going to try to photosynthesize as long as there's sun shining on their leaves. If they can't handle it, it's not good for them. Removing leaves so that the plant doesn't get too much light can help. It'll grow more extensive roots as the new leaves grow.

It's my personal opinion that older leaves tend to be less adaptable to light changes than newer leaves, and in my experience, this seeming lack of adaptability can slow the growth rate and of plants (although much more so in some species than others; I don't have that much experience with basil, so it might not be a big deal)—although what I was saying above was mostly not about adapting to light changes, but that's why I suggest removing older leaves, instead of just any leaves.

Now as for these basil plants, looking at them again, and reassessing the situation, I think they're really too young for this to matter much; and, they've been transplanted for a while now (and are probably recovering, as well as shedding the leaves that are important to shed anyway, over time). What I'm talking about is a lot more helpful for older, larger transplants with more than a few leaves (how old the leaves are seems to matter, too). Ideally, you'd remove any leaves that you're going to remove *before* the transplant (to reduce the initial shock). Removing them afterward isn't as much about the shock as it is about those old leaves not being as adapted to the new environment as the new growth. I tend to think pre-transplant leaves are more prone to disease, too, but that's a different topic. For some reason, I didn't realize just how immature the basil plants were. Immature plants tend to need what leaves they have a lot more, I think; it's difficult to say what would be best here. If it were me, I might remove a couple of the very bottom leaves that don't look so great, but that's about it.

Younger plants don't often grow new leaves or shoots as easily when they're missing leaves.

Basil may be able to drop leaves faster than a lot of plants, naturally, due to how thin and soft they are—but not all plants shed their leaves so easily, even when they're in transplant shock.

• Too much photosynthesis? If transplants are watered thoroughly they will recover. The key is sufficient water. Basil transplants easily and the OPs plants show little sign of any problem imo. They will recover. I think you are really over complicating a simple process.

• Removing leaves from cuttings is entirely different.

  This paper deals with the myth of removing growth on transplants. It deals with trees and shrubs rather than annuals but the principles are the same.

@floral That paper is about pruning top growth—not about removing the oldest/older pre-transplant leaves.

Although watering sufficiently can definitely help, it's not a cure-all for transplant shock (nor for the long-term effects of it), even though it might be sufficient to help the plant survive in most cases, if by chance you avoid doing some detrimental things (like transplanting during full sun, in full sun, in high nitrogen soil, at a bad time of the year, without sufficiently hardened plants). What I was suggesting was not over-complicating the process that people usually do, but rather I was suggesting additional and supplemental things you could potentially do to improve matters (it's not all or nothing; you can be as complicated or short and savvy as you like). However, it should be noted that too much water can inhibit photosynthesis; whether that's good or bad, I'm not saying. And, if leaves don't get enough water (which they might not if they're wilting), they may seek to retain what water they have by permanently blocking off their stomata (which impairs the function of the leaves, even after they stop wilting—but some plants will only grow so large; so, if they have lots of leaves with stomata blocked, that could hinder the plant from getting all the light it needs to perform as it should—at points when large amounts of light could be helpful). However, I really don't know how drought-stressed leaves need to be before they block the stomata. I'm not making any claims there.

I agree that the basil plants will probably recover and that it's not absolutely necessary to remove any leaves. I wasn't meaning to say otherwise. In my previous paragraph, I was not indicating that the basil was wilting (it's curling, which is different), but rather I was talking about a hypothetical plant. If I mean a specific plant, I like to address a specific plant.

I agree that it's possible that the plants may not have been experiencing transplant shock at any point. It looks to me like they're still getting used to being outdoors in stronger sun, with probably drier air. That's not the same thing as transplant shock (even though strong sun can trigger it).

I'm not meaning to claim that I understand everything here. I have a lot to learn, including about plant biology, photosynthesis, respiration, transpiration, etc.

The oldest leaves are top growth. All leaves are top growth irrespective of where they are on the plant. As long as leaves are green they are working. There is no reason to remove them. And again, as far as I can see, those plants are actually fine. Note that the OP stated that the plants became turgid over night so they are reacting healthily.

I know that underwatering is not the issue because the soil is still soaking. Overwatering actually may be a possible issue too. I am avoiding watering to slightly dry out the soil to a more ideal dampness for the basil. There appears to be a few days of warmth but cloudy days that should help the plants perk back up. Thank you for everyone that has given input on my plants! I’m just hoping that this is just a minor issue that will clear itself up in a week or two. And also, the leaves just loose turgor during the sunny parts of the day and stiffen back up at night, except for one.