John Chapman's Southwest Gardening

September Garden Calendar

By John Chapman

Soil preparation: This is the most important step to successful gardening in the Valley. If the soil is not right with organic material and the pH is not right, plants will not produce. So do it right. There are no shortcuts to producing a great crop of vegetables and ornamentals. Spade the garden beds to a depth of 8-12 inches - turn the soil over, break up clods. For each 100 square feet of garden area add 2 pounds of

16-20-0, ammonium phosphate; 5 pounds of sulfur and 5 pounds of Ironite. If you plan on growing onion use gypsum in place of sulfur because sulfur make onions strong and hot. Spread 3-6 inches (eight to 10 two-cubic-foot bags) of compost, forest mulch or steer manure. Mix all this together, water it well and when the soil has dried to just moist – plant. Keep in mind that some flowers may need other soil amendments, like bone meal and super treble phosphates. Bulbs are a good example.

Flowers: Your flowerbeds should receive the same attention, as the vegetable plots, but planting of most flowers should be delayed until mid- October so stay tuned! If you're a bulb fancier, it's time to prepare the soil. Some bulbs like tulips and hyacinths need to be chilled in a paper sack in the vegetable drawer of your refrigerator for four to six weeks or they won’t bloom. Bearded iris need to be divided about every three years for good healthy plants, and fall is an excellent time to perform this task.

Roses: Hose off the foliage 1-2 times a week to remove dust, spider mites and potential white flies. Water roses about every three days and apply about five gallons of water to each plant. Right now, prune out the dead canes and weak top growth but no heavy pruning. Remove any suckers below the bud union; cut off any spent blooms back to the first five-leaflet stem. About the 15th, fertilize with ½ cup of Rose Food, such as Organo 4-12-4, and Ironite. Remember; water-fertilize-water. Water first, sprinkle out the fertilizer and water it in deeply. To encourage new canes up from the base, sprinkle ¼ cup of Epsom Salts (magnesium sulfate) per bush.

Citrus: If you didn’t fertilize your citrus during August now is the time to do it with ammonium sulfate, 21-0-0. If you already have a balanced fertilizer like 16-8-4 that is all right too, but citrus farmers say that nitrogen is all that is needed. This last fertilizing will help make larger fruit. Be sure to sprinkle the fertilizer under the outer two thirds of the canopy and beyond because that is where the feeder roots can take it up. The roots can’t use fertilizer on the inner third next to the trunk so it is wasted. Citrus fruit begins to enlarge after its no-growth period during the hot summer months. Citrus fruit drop is natural thinning process, worsened by hot dry winds. Lemons can be picked as needed later in September even though the fruit is still green. Lemons will not get sweeter, just juicier. Cool weather turns citrus orange and yellow; color is not an indicator of ripeness. We traditionally use limes in a green state but if allowed to fully ripen they will turn yellow. This is a good time to get inside your citrus trees, trim out the water sprouts and clean out any dead wood. You'll be rewarded this winter when it comes time to pick the fruit. Trim off any sprouts below the bud union.

Trees and Shrubs: Watch for signs of chlorosis (yellow leaves with green veins), a sign of iron deficiency. If you have this problem, spray the leaves with chelated iron with a spreader sticker added. Continue to deep water on the summer schedule, which is about once a week for shrubs and every two weeks for trees. Water native shrubs every two weeks and native trees once a month. We can lengthen the irrigation schedule in October. This month through October is excellent - in fact the best time for planting non-frost sensitive trees and shrubs from containers. Soil temperatures are still warm enough to help roots establish quickly. After planting, water deeply. Dig a planting hole about three times the diameter of the root ball and no deeper. Sides of the hole should be rough or sloping. Do not pack backfill. Set top of root ball at or slightly above soil surface. Form irrigation borders just outside root ball. Use water to pack backfill. Spread mulch on the soil surface to a depth of 3 - 4 inches, keeping mulch away from tree trunk. Do not prune unnecessarily. It is a good idea to wrap trunks of new plants, which are frost-sensitive with burlap, newspaper or cardboard for freeze protection through the winter. Don't over water after transplanting trees and shrubs. Too much water can drown and rot the roots. Just keep them moist.

Pecans: The seasonal shed of pecans usually occurs late summer or early fall. These are defective nuts, partially rotted or not fully developed. Sometimes shells are completely empty, no thanks to the leaf-footed plant bug. Control is rather difficult.

Don't worry about it! That sap that gets all over sidewalks and vehicles parked under pecan trees comes from aphides feeding on your leaves, any treatment is impractical, the tree has plenty to spare so either live with it or park your car elsewhere.

Tomatoes and Peppers: If your tomatoes and peppers look terrible but are still alive, trim them back to 18 inches. Remember the root zone is as large as the foliage, so sprinkle one-half cup of ammonium sulfate (21-0-0) and Ironite on moist soil over the entire root zone and water in during the second half of the irrigation. Caution: After pruning, apply 21-0-0 fertilizer only once, and water deeply for an extra burst of new leaf growth. In the three weeks go back to using a balanced fertilizer, 15-30-15, 15-15-15 or Tomato Food, and Ironite etc. If you continue to apply 21-0-0 you will have a very large tomato bush or vine and few tomatoes.

Strawberry Renewal: If you lost most of your strawberry plants, you are not alone. Dig up those that remain. Transplant them into six-inch pots. Those that have little ones attached put in separate pots but close to one another so Mother can still nourish the young one. Continue to use the usual nutrient solution of the tablespoon of houseplant food to a gallon of water to get good growth. Rejuvenate the bed as stated above or, better yet, plan on putting them in another bed to avoid diseases that attack strawberry plants.

Lawns: If you plan to over seed your Bermuda, stop fertilizing. Over seeding should not be undertaken until temperatures stay below 95 degrees, generally about the third week of October is the target window. If no over-seeding is planned, add about 10 pounds of Ironite for every 1,000 square feet. If you use ammonium sulfate, 21-0-0, instead of Ironite, you must water deeply to prevent burning and you will have to mow more often. September is also a good month to lightly dethatch Bermuda grass just before you over seed it.

Veggies: As the intense heat subsides and temperatures drop below 100 degrees, seeds of cool season crops can be planted. Hold off on transplants of broccoli, brussel sprouts, cabbage and cauliflower until after September 20 (or even into October) and wait for temps to stay below 100. Listed below are some veggies that can be directly seeded in the garden:

You can also put in transplants of Tomatoes, Lettuce, Strawberries, & Onions. Plant leaf lettuce varieties. Leaf lettuce just keeps giving for months. Head lettuce is tricky to grow and you only get one head per plant and it’s done for.

If you have a specific question for John please leave them on his voice mail 480-898-5636 or email him at john@johnchapman.com . For more of John Chapman’s gardening tips listen to 620 KTAR radio Saturday morning 7:40-8AM and TV on Jan D’Atri’s “Heart and Home” Sundays 12:30 pm repeated Monday evenings 8pm on Broadcast 27, Cable America 4 or Cox 13.