i use cardboard, sometimes 2 layers, with a woody mulch on top. it seems to stop weeds for a year or 2, then you can remove the larger chucks, and add another layer, and more mulch... just keep 3 to 4 inches away from the trunk. rain will soak in from around and even from the top. its not been an issue.

it keeps the weeds down to 0. at least for a while. ikt keeps moisture in the ground too.

getting 2 female papaya is pretty unusual. especially solo/strawberry. they are bred to be %66 bi-sex.... papaya sometimes do change sex. at least from males to bi-sex... i think from female to bi-sex also. stress supposed to be what triggers it... what farmers have used in the past is to drive a nail in the trunk.

too much or too little rain can spark a sex change as well.

one changed for me once after i topped it. i cut the top 4 inches off... i do that on all my papaya anyway to keep them short. they will start to branch out when you do this though... i keep mine to 1 or 2 "branches"

papaya like deep loose soil. it doesnt have to be very deep, but if its not, they will send roots 20ft looking for water, even if the plant is only 8ft tall.

science has found that plants will share nutrients if they have the proper soil health and biology... Fungi can go from 1 tree to another several feet away. and if 1 plant has a higher need for zinc, and another has a higher need for phosphorus, they will send those minerals to where it is needed.... woody mulch is the best "highway" in which to do this... (cardboard helps too, especially since it is continuous)

it may take months, or even a couple of years for a good fungal pathway to be established.... it is possible that one exists already, or parts of one here and there around tree roots which have died and rotted away years ago.

you can buy mycogrow or King Stropharia to innoculate

mycogrow has several species, but with King-Stoph you get edible mushrooms :)

https://www.google.com/search?q=MycoGrow

http://www.fungi.com/product-detail/product/the-garden-giant-mushroom-patch.html

i actually take a shovel full of soil from 3 different sites, under old established trees from a "wild" area that was never clear-cut by humans... this ensures you get a very diverse set of organisms suited to your climate. - make sure the soil touches the roots, or, just an inch away. you can scratch it in the top 1 inch above the roots and add mulch on top. - dont let it get too dry or out in the sun too long. dont use chlorinated water on it, or to water the first couple of weeks.

so, your on a good start... keep us updated.

Thanks greenman,

This whole strip, from about 3' to the right of the smaller trees to the far edge, I had cleared and built up about 3 to 4 years ago. It had been the same as what is behind the far edge, ulehe jungle. I brought in cinders and mulch layering them, then tilling them together. That resulting soil needs more organic matter which is part of the reason I'm adding more mulch before bringing in the apple bananas. That soil is fairly thin overlaying lava rock. I'm in a high rainfall area getting about 150"/yr. Even so, those papayas had sent out a good heavy root system that was a job to get out of the ground so that it can be tilled. Our domestic water is catchment. So, if I ever do need to water, chlorine is not a problem. My greatest concern is the high rainfall leaching the nutrients out of the soil.

The reason I think the papayas were from a commercial seed, maybe even a GMO type, is due to their having "huge" flowers and growing much faster than others around the lot. I have a third papaya, a volunteer, that is also a female, but the flowers are about 1/3 the size and it's growing much slower. Yeah, that makes 3 out of 3 female trees. Something doesn't seem to be right about that. I still have the volunteer but it will have to go soon because it is crowding an Ota avo just to the right out of the photo.

I need to bring several more cart loads of mulch over and spread it around. before beginning the tilling. I want more organic matter mixed down into the cinders below.

I have used brown paper grocery bags, opening them up into a single layer, to hold weeds down around a pineapple planting. Your right, it does seem to work well for about 9 months to a year. Then the weeds start creeping in over the edges and covering it. Another brown paper layer over those weeds should work for another year or so. We'll see.

I think I'll run into town today to pick up a small roll of flashing to put around the tree trunks so that I can mulch under the trees and cut the grass and weeds without damaging the trees. Mowing the area discourages weeds and encourages grass growth which ends up crowding the weeds out. I'm not going to worry about grass growing under the trees. All I want to do is cut it right up to the tree trunks.

Unless anyone gives any reasons not to, I'll go with my estimates of how far to keep away from the trees when tilling the mulch in.