Sunlight? They do love sun and like to bask in it. Obviously they are leaning to the sunlight. Plants do that naturally. MY 30 + blueberry bushes all lean towards the east, where its sunrise. The west is got many tall shade trees and the bushes dont see the sunlight in the west after about 3 PM, so they lean. This has been natural for well over 35 years now. Basil, like many other herbs do best in full sun, and planted in regular outdoor soil. They tend to get to cramped in a small pot and HATE too much water. Adding fertilizers can also affect the leaf taste. Leaves that turn yellow are getting too much water. If possible, try to plant these in very large pots and give them more direct sunlight. My basil seedlings also lean, but once planted outside, they tend to grow straight up, or at least bush out quite a lot. Its all quite normal and I have seen it with cilantro, dill, and and many other herbs that are started in small pots. Even my tomato plants lean a lot, and must be staked when planted outside. If I let the stems rest on nearby pots and their soils, they start rooting there too. NOT good if you are planting them in individual locations.

Turn the pots a little every day to expose the plants to the light evenly.

hi,

thanks for your replies. actually i totaly agree with you about sunlight exposure, the two pots have only one hour a day of full direct sunlight exposure. but that is all i have to give, i live in an appartment and i don't have access to such place where the sun is always there, this is one thing. the other thing is watering, as i told the temperature is high and also tend to vary from high to low, so when it gets higher i try to provide more water then the temperature gets low. also i don't know what is the appropriate quantity of water to use with every pot, so i would appreciate giving me an idea about how much water to use?

there are things that i did and i don't know whether i did worng or right. one is the two pots had plants in them before and they died because of white small bugs, some infestation i don't know about, so they were left for a year or so without plants. then when i decided to plant something in them i took the soil out, and put it in an oven, then took it out and turned it into powder, put it back into the oven until it completely dried and i cleaned the pots then put the soil back. so the soil now is so black and a little thicker than before.

another thing is that there were pieces of limestone ito the pots that i threw away, and now that i know that plants need calcium i don't know if they definitely need some calcium carbonate source (new limestones, pieces of chalk, lime powder) in the pots or not? and how to distribute it? with a sprayer or put it solid deep into the pots. i don't have access to consumer home fertilizers, so i have to use elements from my surrounding environment.

so is there any way to remedy my plants with the conditions i provide or i have no chance with basil or herbs at all?

thanks again.

Your just going to kill the plants with all that unnecessary effort of adding calcium, limestone, oven baking, etc. Start with clean pots and good quality STORE BOUGHT potting soil. Its already got enough of the necessary components in it, unless you can't afford to get some soil. NEVER use soil dug from the ground. Baking old soil in an oven does not help it in any way, except make a stinky kitchen, and kill off any benefical microbes.. With good quality potting soil and a little watering, it should be fine. Bugs get into soil all the time, and even for that, if the plants are healthy enough, they should do just fine without extra effort or an attempt to 'sterilize' the soil. Only an hour of sunlight is not acceptable for basil to grow, Nothing you can do will get it to stay vertical. My basil is started from seeds indoors and doesn't grow vertically very well, as its always under plant lights at about 18 hours per day. Once planted outside, it does grow nice and straight. The watering varies with the kind of soil as well as the pot size. Adding calcium or any other item is not useful for the plants health. Some herbs like cilantro do quite well, provided its cool, and with minimal direct sunlight. Dill is also a good plant to grow in a pot. About the only choices for basil would be the very short bush type that seems to do better in less sunlight. The basil I grow gets to almost 5 foot tall, but I also grow a type that is bushy at about 1 foot tall. Water only when the leaves show signs of wilting due to the lack of water. Its better to underwater than to overwater. I can't tell you the exact amount of water to use as I don't know the pot size or what kind of soil it has. Some potting soils have additives that are for 'moisture control'. These soils work well for high heat areas and would help to retain some water. I use this kind of soil for my flowers in hanging baskets. If the soil totally dries out every day, it may need a bigger pot. There is also a polymer granule that can soak up water and turns to a gel. This stuff is great for places where there is too much drying out of regular soils.

"200ml (a glass of water) of water twice a day (too much?)"

too much water for basil. I grow some of my basil under a pergola just because it's convenient to the back door for picking at night, and I think you will be fine growing it on your balcony with your temps, it wont get the heat stress of being out in full sun all day. your little seedlings only need a touch of water here and there. If they wilt, they're not getting enough water but they can handle the soil drying out, you dont need to keep them constantly moist.

what I do with basil is raise them in punnets until they get to a bigger size and that way I can control the water better, once they are big enough they get planted out into the garden or pots and they only get water about once a week even in high temps.