Hi Everyone! I need some citrus help. I grew a grapefruit tree from seed almost 10 years ago now. It lives indoors in a pot and has never flowered, it does spend summers outside. I am wondering if there is something I should do specifically or if flowering for indoor grapefruits is really not a thing? My second question involves lemons. I have been trying to grow a lemon tree from seed and am having no luck. I use organic lemons and tried putting the seeds directly into a cup with soil and covered with ventilated clear plastic. I have also just placed a few in a wet paper towel to see if they would germinate easier that way... no luck their yet either. Any and all advice is greatly appreciated!
Welcome to the forums. Some people, based on the node theory(*) on the maturation of citrus, suggest it's nearly impossible for a grapefruit seedling to reach maturity indoors. Yet there may been instances of people claiming otherwise in these forums. There are two ways to encourage a mature tree to produce flower buds so you might try that. You can read about them in this post. (*) Node count theory, as explained by Dr. Manners in his own words, can be found in this thread in an external forum. Keep trying with the lemon seed. Choose ones that are large, plump and which will sink to the bottom in a bowl of water.
Citrus have a very particular pattern: if they are made from mature wood they will tend to flower right away, but if they are made from seed it can be many years (typical is 7-10) or never flower. Most good growers will propagate mature wood, either as cuttings, air layers, or grafts. Citrus from seed can take a very long time to flower if they flower at all, and then they may not be true to form. If you have huge patience and like to try your luck at things then growing from seed is ok, otherwise make sure the citrus plants you get are made from mature wood. Lemon seeds should at least sprout. I have found that they do need a lot of heat and moisture to do so. If you do not already have a seedling heating pad then it may be what you are missing. Also, citrus seed rot easily, so if not using sterile media and clean seeds it is possible they are dying from fungal infections. Make sure you are using at least clean media, such as a good soil-less seedling mix, and you may want to ensure the seed are clean. I like to spray them with hydrogen peroxide and then rinse them off.