When should I transplant basil from seed trays to pots? It's been 4-5 weeks now and they're still so so so so tiny. I tried looking it up but all I could find was *how* to transplant, not *when". Is there a particular size or time I should be aiming for?
so right now all you are seeing the ✨ cotyledons ✨ aka the first leaves aka false leaves of the basil seedling. the purpose of these leaves are to indicate if there is light for the plant to continue to grow. if yes, then roots will continue to grow and then the true leaves will begin to form. if no, then it stagnates in growth until it gives up in the if/then statement and withers away.
for basil, this should only take up to 5 days. since we are well past that, let's do some troubleshooting!
1. give it some real sunlight. i'm not an advocate against light lamps, but i'm also not a fan unless that's where the plant is gonna be its entire life. If the real sun is not an option, move the false light closer to the babies. make them REALLY feel it. this will trigger the "yes sun" and start to grow as expected.
2. basil is actually one of the HARDEST plants to make happy. it wins the crown for best drama queen. it adores humidity and heat since they are originally from tropic regions. if you can, dome them with either a dome specific for your tray, with a homemade one with plastic wrap, or thrift a glass bowl and overturn above them. this will trap the moisture and make it extra humid. growth can also be stunted if the soil isn't 75°+. i don't spy a heat mat under it, but a heating pad for a human works in a pinch; just make sure you add a waterproof layer in between the human heating pad and the seed tray.
once the solution has been fixed, then the answer to your question will be to transplant once you have at minimum four true leaves (or six leaves total, if the cotyledons are still present). if their final home is outside then don't forget to harden before fully transplanting!