Those are impressive, are they in a supersoil?
Over the course of the last three years, I have had the pleasure to talk and work amidst several exceptional FARMERS in California. Five common threads that ultimately aid to an amazing season are..
1). The wider your holes the bigger your trees... If your trees roots can extend horizontally 5ft or more (12x12 hole works wonders) then your boughs will follow. 2). Prominent sun exposure. At least 8hrs. - 10 to 14 significantly better.
3). Home brewed aerated teas alive and thriving with beneficial microbial (bacteria & fungi) inoculants to promote plant health and soil amendment uptake. 4). Hopefully your thumb is a shade of GREEN... And number 5). Build a Generator of Soil.
As far as soil and amendments go, the following recipe is by far one of the best for overall production and quality of your harvest:
Soil & Amendments for Gargantuan 8lb. to 12lb. TREES (working in 10x10 to 12x12 holes)!
1). 20% worm castings
2). A special mix at a local compost/worm farm at equal proportion to the worm castings.
*Special mix contains: Green compost, chicken manure, cow
manure, rice hauls, and perlite.
3). Five bags of perlite.
4). Optional: Cut above mix with... Native soil, (2-5 bags) of
Happy Frog and or Ocean Forest (your favorite potting soil) -
depending on your holes/containers size. (Save
one bag of Happy Frog for each tree to transplant directly
into their new holes once your clones and or seeds have
hardened off).
5). 1/2 bag of oyster shell
6). 1/2 bag of steamed bone meal
7). 96oz of Rock phosphate
. 96oz of Azomite
9). 96oz of Glacier Rock Dust
10). 96oz of Gypsum
11). 96oz of Green Sand
12). 96oz of Feather Meal
13). 64oz of Kelp
*At this point it would be best to pull out your tractor... If you don't have a tractor use your rototiller and blend your ingredients to create your, "GENERATOR of SOIL!!!"
14). Add approx. 1 cup of Mykos (Pure Mycorrhizal Inoculant) dispersed around the roots of 3 to 5 gallon bags during transplanting of tree to hole or outdoor (large) bins/containers.
This is not a cheap amalgamation... However, if all goes well during the season, you will successfully prevail into harvest with a permanent farmer's grin ... You will have the BIGGEST Marijuana Trees growing on your farm that you have ever seen. Miraculous, Amazing and Magical!!!
Good Luck & Many Blessings!!!