Soil:
The major types of soil in this are black soil, loma, and tepetate. Black soil is clay: heavy, gets too dry and too wet. Lots of nutrients. Loma is sandy, from rivers, with no organic matter. A good mixer for clay. Tepetate is desert caliche: white to light brown, alkaline, no organic material, will not support plant life except cactus (found in Balcones). Tesotle is volcanic stone.
Alfonso mixes his own soil: Organic compost (leaf mold, mushroom, etc.), which gives the soil structure, black soil and loma (using less black soil than the other two). Organic composts can be purchased at local viveros. Home Depot sells composted sheep manure, as does Mega. Caution against uncomposted animal manure: it is very “hot” and can damage plants. Horse manure contains white soil grubs. All may contain weed seeds. Animal manures need to be composted one year. There is a mushroom farm on the way to Comonfort where mushroom compost can be purchased, but easier to get at local viveros. Do not compost eucalyptus leaves. Toxic.
Our water here tends to be very alkaline from the wells, as the desert soil from which it perks is very alkaline, with no organic material and 100% calcium. Native plants do well with alkalinity, but ornamentals do not. They need more acidity. Excess alkalinity shows itself through yellow leaves, iron chlorosis, although too much water can also cause yellowing, especially on bougainvillea. All symptoms of heavy soil. Alkalinity stops nutrients from reaching plant. We must add organic matter. Mediterranean plants do best here; very difficult for azaleas & camellias. He also recommends acid for citrus trees. Hard water = alkalinity. Vinegar can be used to change the pH of the soil. 1T/gallon of water can be poured in pots to change the pH. Use one a year or once every 6 months. Wet soil before you use the vinegar mixture.

Fertilizers:
Use regular fertilizer once a month. You can use Miracle Grow monthly for two months, and then use Miracid for one month. He adds compost twice yearly and turns it into the soil. The two types of fertilizers are synthetic and organic. Chemical fertilizers are designed for certain things: for leaf growth, flower growth, etc. Balanced fertilizers have the same three numbers on the bag, such as 20-20-20 (20 = 20%, etc.). Nitrogen is the first number: grows leaves, turns leaves green, such as grasses, lawns. Phosphorus, the middle number, is for flowers and fruits. When the 2nd number is larger, that fertilizer is for flowers and fruits. Potassium, the 3rd number, is for roots and strengthening of the plant. Alfonso uses 20-20-20 for general fertilizer. There are also secondary nutrients, called micronutrients. You can buy 17-17-17 by the kilo at El Sirco, across from the Bus Station. This works fine. This does not have micronutrients, however, and is too heavy for pots. In the soil, add once per month and turn it into the soil.
Ammonium sulfate is pure nitrogen and is used for lawns. Water first, and then after application. Also good for bamboo and ficus. Safe for pets. Use once per month. Don’t fertilize in winter (Dec., Jan., Feb.), as new growth is susceptible to cold. There is some dormancy here. In the rainy season, fertilizer washes quickly from pots. Natural fertilizers are manures and compost. Read compost notes from above. Compost should have light scent, and look like soil. Best are from chicken, sheep and goats. Worm castings are also excellent, but worms should not be allowed in containers, as they create harmful air pockets around the roots. Purchasing chemical fertilizers: Alfonso can get them for us from a company called “Serviagricola” in Queretaro. We discussed that I had been there, but it is very far away on the highway to Mexico City, and difficult to find in an industrial area (they had recently moved, but I had been to the new location). Since Alfonso gets wholesale prices, we agreed that it would be much easier to order what you want through Alfonso, and he will have it for you at his store adjoining his restaurant, La Crepe. I will scan the catalog from Serviagricola and attach it to this document, so you will know what is available. You can purchase Osmocote in large bags. Because it is expensive, it is best for pots. Chemical fertilizers have a long-term salty effect. Watch for white build-up as indicator. Right now, it is easier to get chemical fertilizer than organic here in Mexico. Always use a pitchfork to turn soil after fertilizer application.

Insecticides:
Whitefly is hard to kill; infests lantana, sage. Spray as soon as you see a few. Organic insecticides, such as pyrethroids, are the safest. “Ambush” is one of these, although it is NOT SAFE for fish and honey bees. Use the weakest solution frequently. We then had a discussion saying that the presence of whitefly, etc. often indicated a cultural problem (wrong location, etc.), and that meeting the plant’s proper cultural requirements was a better solution than using toxic chemical pesticides. Toxic pesticides kill the good bugs along with the bad. Unfortunately, Mexico’s importation laws have made it very difficult for the less toxic pesticides, such as the non-toxic Neem oils, to get from the USA to here. Systemic vs. contact insecticides: Systemic become a part of the plant. Contact insecticides are generally safe when dry, such as “Ambush.” For ants, kill outside your walls. Don Pedro sells a bait from Ortho. Best to find the ant hole first than to just scatter bait. For grub worms: diazanon. For slugs: shallow bowls of beer, or bring Sluggo (non-toxic to birds and pets) from USA. You can create your own low-toxic spray with laundry soap and water. The cheaper the soap the better. He uses 40/60 soap to water, then puts it in a spray bottle. (Note: there are formulas on the internet using liquid dishwater detergent that may be easier to spray). Fungicides are for spots on leaves. Cuprabit is the safest, at El Sirco.

QUESTIONS FROM ATTENDEES:
1. My bougainvillea doesn’t bloom! Too much water; too little sun. Wait until soil is dry before watering. Epson salts are good for them (ammonium sulfate).
2. My tree’s roots get into our plumbing! Better tree to plant close to house is common privet.
3. Why isn’t my orange tree growing big? Soil too heavy; not enough sun. Citrus needs full sun. Also, orange trees don’t live forever. But at 10 yrs of age, should be OK.