Question
I live in Arizona and the soil here is very perplexing with regards to growing vegetables.  I have a small garden (3?x 25? and I like to grow a few things to eat each year.  I usually start by tilling in some steer manure and any compost material I have.  When the plants mature I end up with bottom rot on the tomatoes so I am told to add Gypsum.  That solves the problem but the tomatoes are still very small.  I grow other things but they don抰 look or taste right and I get told that I need more sulphur or magnesium or potassium or a host of other additives and still my garden doesn抰 produce as it should.  The vegetable are scrawny and the tomatoes (even the BeefSteak variety) are only about 1-2?in diameter.  If I buy every nutrient that people tell me to add, I will have 50 lb. bags of 20 different chemicals.  So my question is: Is there a good, all-around fertilizer that will supply all the nutrients necessary for my garden to grow decent, edible vegetables?  If so, what is it and how often do I apply it?  Any other suggestions?

Answer
I am going to surprise you and tell you that the fewer chemicals you add, the better. Tomatoes require a fairly neutral ph level (near 7.0) for solid production. By adding gypsum, you are increasing the alkaline level. Depending on what level your soil is, that could prove detrimental to the plants.

I would create a raised bed (10" or higher) and add 2 parts peat, one part aged manure (aged at least 3-6 months), and all the compost you have available. Mix this in with some loamy soil high in organic matter. You can usually purchase this at most landscaping centers. I also mix in 3 tsp. of Epsom salts in each planting hole to prevent blossom-end rot on my tomatoes, peppers, and eggplant. Although this product is primarily magnesium sulfate, what it does is assist the plants in the absorption of calcium, the nutrient required to prevent bottom-rot.

Keep in mind that blossom-end rot is very common in most gardens, and primarily affects the first harvest. This is due to the plants' roots not being adequately mature enough to absorb calcium and other nutrients. Epsom salts have been proven to be beneficial in alleviating this condition.

In regard to the size of your tomatoes, do not apply any chemical fertilizers until the first tomatoes appear. I then dissolve the Epsom salts at a ratio of 3 tsp. per gallon of water and spray them liberally on the plants. I also use a water-soluble fertilizer high in phosphorus but low in nitrogen. Nitrogen promotes lush foliage at the expense of large fruit and a strong harvest. That is why I would use a small percentage of manure since it is high in nitrogen. A good NPR ratio for tomatoes is 10-30-30, or something close. Just make sure the first number on the package, representing nitrogen, is the smallest of the three.

Finally, be sure to mulch the plants with 2"-3" of straw to help retain moisture and cool the soil. Water deeply as needed. Shallow watering causes the roots to reach for the surface, which eventually weakens the plants and their production. I would also recommend indeterminate varieties since they produce over a longer period of time, giving them a better chance to overcome early issues as described above.

I hope this answered your question. Good luck, and please write again if I can ever provide assistance.

Regards,

Mike