Our farm gets 600mm of rain and has a 9 month dry season. That being the case, getting a taproot to the water table is of utmost importance in establishing fruit trees here. We have many mature mango trees in our area that bear copious fruit every year, even after minimal rainfall years (last year was 235mm). The same is true for many native fruiting trees. Established orchard theory usually recommends seeding fruit trees in tree sacks/pots, and outplanting several months to years later, when the plants are deemed large and tough enough to survive "real world" conditions. This means half a year or more (50-100cm) for Annonas, over a year for mango seedlings so they can be grafted in the nursery, and even several years of slow growing trees like Imbe. My concern, though, is that waiting this long would seriously hamper taproot development. Does anyone have experience or thoughts on this?
Last week I dug up a native tree (non-fruiting acacia) that I had sowed in a tree sack in February. I say "dug up" because the taproot had escaped the sack and was already nearly a full meter down in the soil. In 3 months had produced 30 cm of above-ground growth and over a meter below ground. This species should almost certainly have been outplanted within a month of sowing regardless of plant size, or just direct planted in the field. Does the same apply to fruit trees in my kind of environmental conditions? Or am I overestimating the importance of early taproot development?
Do tap roots "wait" when they hit the bottom of a nursery pot, and how does this affect their eventual development?
Does anyone have experience with survival rates in direct seeding vs transplanting fruit trees in low rainfall conditions?