Hi Sammy. I understand your need to install a good ground. The previous
postings to your questions have given you some good information. We can
probably give you more help if you tell us what country you are in?
Mexico, Veracruz state. If anyone tell me where to find constructiom codes
in the web for Mexico, I'll appreciate it very much.

what materials are accessible to you? Are you able to purchase ground
rods
and #6 or #4 copper wire?
I'll investigate this subject. At least I can found copper and galvanized
steel pipe

What are the soil conditions in your garden? Are
you in a dry climate or do you get rain?
It is a tropical climate, I think like Florida. Soil is dusty, very small
grains, humidity is high.

If not how about bare copper wire?
Copper wire is available also

What type of electrical service is coming into your house?
How many volts and amps?
110 Volt/60Hz. I'm not sure about amps

Thank you very much for your interest.
Sammy