I am growing cactus, lemons and some strawberry in pots. I just bought this peat moss from my local store to fill the pots with it(only with this) On top of it it says tree and vegetable. Is it okay to use for lemons and cactus aswell ?
For your lemons and strawberries this will probably do (use pots with drainage holes though), but for cacti it is advisable to use something else (with better drainage capacity, and less peat). You can buy special cactus potting soil (e.g., Pokon), it contains more sand or gravel of some kind to encourage proper drainage. You can also make your own cactus substrate, you can find many recipes on internet. But if you don't have too much cacti, the easiest is to buy special cactus soil at the garden center. I usually buy cactus soil in bags of 5 L, and I mix some perlite into it (like 20-30%), just for the extra drainage.