I am getting ready to grow some vft from seeds and was just wondering how long it takes for the to grow big enough for them to eat.
According to the International Carnivorous Plant Society website, it will take two years before they are large enough to comfortably consume a fly.
I recall growing seedlings in the past and giving up on them before a year was up... I'm impatient.
Well my seedling Flytraps are about 8 months old and are still only about 1/4 inch across. Next year they will hit a growth spurt and get an inch or two tall, but will only be able to catch gnats and fruitflies. Right now they are lucky if they catch a protozoan.
Never worry about feeding carnivorous plants overmuch... they usually catch plenty of insects on their own... In any event, as the carnivorous plant experts indicate, they really do not eat insects, but light, like other plants. Insects are just fertilizer for them, so you could see them as being like vitamins. Nobody is going to die from not taking their vitamins every day... but they will starve if they do not eat real food. Same for Flytraps. Just give them light, peat moss and perlite or sand mix with no fertilizer, and mineral free water and they will take care of the rest.
They need a few years. A faster way is through pulling leaves from the base and sproutin them. It starts them off larger and gives you a cluster of plantlets.
I bought two VFTs from walmart a few months ago. Wasn't I surprised when I found a TINY little VFT growing in one of the pots. Its traps are 1/8". I have them sitting outside above my compost pile and this little trap catches gnats. It can't be very old because I hadn't noticed it when I bought the plant. I would never try to feed it, but if it's catching gnats on its own then so be it.