May not be a good idea to add lime. A 1/16 teaspoon or less would be about the most you want to put in the soil in a pot. Yellow leaves are a sure sign of over watering and lack of decent rertilizer. It may also need a trace of iron. 6 hours of direct sunlight isn't very much. If your drinking water is hard, its natural lime (and calcium) will cause an even higher pH. Most plants do best in a pH of about 6.0 to 6.8.

Basil needs lots of sun and warm temperatures. Either your plants were stunted due to cool weather early in their lives i.e. temperatures dropped lower than 50ºF for too long or they were extremely pot-bound and haven't been able to recover. The latter is very likely to happen in the small soil volume of a cell pack. I suspect this is the main problem you are having. Most growers stopped using the cell pack in recent years and now grow in 2 to 3 inch pots or larger. The larger pot helps produce healthier seedlings/transplants that can stay on the seller's bench for longer before getting pot-bound.

Yellow leaves can mean a couple of things, not always over watering. Overwatered plants will often shrivel and appear to need water, then die. This is because the roots die and can't supply water to the leaves.

If the yellow leaves are at the bottom of the plant then it is likely pot-bound. Pot bound plants will often drop their lower leaves as well.

An overall yellowing of leaves usually indicates a lack of nitrogen and/or other nutrients. Basil requires fertilization for optimal growth, especially when grown in a pot and even more when it gets watered often, such as when grown in a cocoa fiber lined or clay pot that dries out quickly. I like to plant my Italian type basils in a 12 pot so they have room to grow and don't dry out too quickly. I also grow two plants together in a 17 inch pot (approx. 2 cu ft of growing mediium). This is the bare minimum size for this type of basil which can easily get 2 feet tall or more. At this time of the year you should be seeing several inches of growth every week or so.

Try cutting your plants back by a third to a half, being sure to leave at least half the number of leaves, to try to stimulate them to grow. In other words, if the plant is 10 inches tall but only 7 inches of it has leaves and the lower 3 inches is bare, only cut about 3 inches off the top. I usually harvest healthy plants by cutting even more, down to the second set of true leaves. Otherwise, start from new, larger and healthier plants.

F. DeBaggio

I think your plants are stunted due to cramped quarters. Basil is a fairly large shrub, you know!

Thanks everyone. I think it's probably a combination of adding too much lime (I added WAY more than 1/16 of a teaspoon), the seedlings being root-bound when I transplanted them, and the pots not being big enough (although in theory wouldn't the plants grow SOME until they reached the capacity of the pot?)

Hopefully I'll have better luck next time.

Basil should never get bound in any size pot. My flowers started from seeds, are grown in 2 inch square pots. Once they are mature enough to plant outside, the roots will be about 6 or more inches coming out the bottom holes of the 2 inch pots. Obviously they have no place else to go and the plants need a big dose of water every day, or they wither. That tells me they are wanting out of their pots.