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Weekly Gardening Tips for Your Area


To Do List: Zones 10 & 11

Susan Wells
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September 2012, Zones 10 & 11

Click the image to enlarge this map of the USDA Plant Hardiness Map and find the zone where you live.

Fall to early winter is the best time to plant, allowing the roots to establish over the rainy season. Toss your wildflower and perennial seeds into your flowerbeds now.  Divide and replant perennials. Try new varieties available at your local Home Depot. Think about starting new beds now to be used for cooler season vegetables and other plants. Pick out a good spot, dig in all that great compost you’ve been saving up and go!


  • If this is your first vegetable garden, do a soil test. Most vegetables will thrive in a soil with a pH between 6.0 and 6.8. Adding garden lime will raise the pH. To lower the pH, add sulfur. (Test kits are available at your local Home Depot or you can send a soil sample to your local county extension office for testing.) It is best to choose quick maturing varieties that can be harvested before growth slows too much when the days shorten and the temperature cools off in the fall.
  • Clean and prepare your vegetable garden by removing all plant debris. Do not add weeds or diseased plant material into the compost bins. (Keep turning the compost.)
  • Turn over your garden soil and mix in compost, organic fertilizer or a balanced 10-10-10 fertilizer, before sowing seeds or transplanting. This small task will help to replace nutrients that have been used by the previous crop.
  • Vegetable plants’ basic growing conditions are important. When temperatures are 100 degrees, we need to lower the soil temperature to let seedlings develop. Lower than 85 degrees is best for most seedlings. Using a floating row cover will help cool the soil and keep bugs out. Shade cloth structures, or a light spreading of straw are a big help too, but won’t keep out the pests.
  • Image via Shutterstock

    When you harvest onions, leave the dirt and skins on, to help protect them from spoiling. Store them in a cool, dark, dry location.

    Before transplanting your Brussels sprouts, cabbage, lettuce, peas, spinach and winter squash seedlings, water the bed thoroughly. Gently spritz the seedlings daily for a week.

  • When planting hard seeds, rub them against sandpaper to scarify them or soak them in warm water. This will help them germinate more quickly. Also, filling the planting holes with water, before planting will speed up germination.
  • This time of year, plant the seeds about twice as deep as suggested by the seed company. This will protect them from struggling with higher temperatures since the deeper soil is cooler.
  • Harvest your sweet potatoes this month or next. Allow them to sit for at least a week before eating to allow the carbohydrates to convert to sugars.
  • The prolific okra is in its heyday in September. Make sure you keep it picked daily or it will slow production. Did you know that the seed pods contain up to 15% oil and are only out-yielded by sunflower seeds in trials conducted in the early 1900s? (During the Civil War okra seeds were roasted, then ground and used as a non-caffeinated coffee substitute.)


  • September is the best month to plant Amaryllis bulbs. Remember not to plant them too deep.
  • Calla lilies are best planted in the months of September through January in an area where you have added rich compost and which receives 6 to 8 hours of sunlight daily. Keep the area moist. Water if the surface of the soil appears dry. (If you plant your callas in containers, use a loose potting medium and a large pot.) Plant your callas only 2 inches deep and keep the rhizomes 12 to 24 inches apart.
  • Fall is time to take softwood cuttings of Angel Trumpets, Clerodendrums, Confederate Rose, Hibiscus and Jasmine.  Experiment with any softwood plant material not listed.
  • Finish up fertilization of bedding plants by the end of the September. Potassium (potash, the ‘K’ in the NPK ratio) helps plants with cold hardiness. If you are purchasing a commercial fertilizer rather than using your homemade compost, make sure that the last number is higher than the first, which is the nitrogen, or N, in the ratio). When fertilizing in September, do not use a slow release fertilizer. We want the plants to grow good roots in September, slow down in October, then ‘harden off’ in November.

Image via Shutterstock

Sedums, Echeverias, and other succulents add color to your garden in shades of gray, green, pink, and rose.

  • Compliment the blue rosettes of Echeveria ‘Cante’ with the contrasting chartreuse of Sedum ‘Ogon,’ or the trailing ‘Creeping Jenny,’ or the luscious purple Setcreasea. Each of these plants uses little water and is suitable for container plantings when adequate drainage is provided.
  • The water hyacinth is one of the world’s most invasive plants. Incredibly fast growing, colonies of Eichhornia can double in size in less than two weeks. The plants float freely, allowing them to spread by wind and current. They have infested the waterways of nearly all subtropical and tropical regions. Cultivation of water hyacinth is prohibited in much of the country. If you can, remove them from any waterways near you.

Trees And Shrubs

  • Apply organic fertilizers to roses to encourage the final flush of blooms of the year. Cut strong stems of roses facing outward to encourage new growth. Always cut out diseased wood from your roses, and do not add it to your compost.
  • September is a good time to plant container citrus trees. Purchase a pot twice the size of the rootball, and place into it a plastic pot as a liner. When the tree needs to be transplanted, it should be easier to lift the pot liner. This will also help protect the outer container. Remember that containers will dry out more quickly than the ground, so have a watering plan in place suited to your plant.
  • Newly planted trees and large shrubs need more water for the first year or two. Smaller fast growing shrubs will need extra water for their first 6-8 months.
  • Do not prune back shrubs in the fall. You can remove long shoots, dead or diseased branches, but save pruning for other times of year depending on the plant. Hard pruning at this time of year encourages new growth that can be damaged by cooler weather in the winter.
  • Image via Mediabank

    Encore azaleas bloom in fall and again in spring. Plant them in large containers with other seasonal foliage or flowers. Most Encore varieties are cold hardy through USDA zone 6.

    Feed your azaleas and camellias near the end of September with a fertilizer tailored to their needs.

  • If you pinch off some of the buds on your camellia, you will encourage bigger booms from the remaining flowers. Choose the right buds to pinch off. Take off the forward facing buds, particularly if the bush is tall. On taller camellias, the downward facing buds are more easily seen and they will last longer in rains as the water will roll off their backs.
  • Jacaranda is a popular tropical tree, famous for its delicate foliage and gorgeous displays of purple-blue flowers. Durable and easy to grow, they make ideal street trees. But they self seed easily and should not be planted where they can become invasive. Monitor carefully.


  • September is the last ‘warm’ month of 2012 to establish a turf lawn of Bahia, Bermuda or Centipede grasses. Each of these needs warmer weather to set a strong root system. Bahia can tolerate filtered shade. Bermuda prefers full sun.  Centipede grows best in full sun but can tolerate light shade. (Use caution and don’t over water a new lawn. A lawn with a strong, deep root system can often go a week or more without water. )
  • If you didn’t dethatch your Bermuda in the spring, consider doing it in September. This month will be warm enough to stimulate new growth, ridding your turf of muddy spots during the winter. If you aerate as well, allow the soil plugs to remain on the turf.
  • Mole crickets need to be controlled with bait in Bahia and Bermuda grass. Sod webworms also infect Bermuda. Centipede grass has fewer pest issues. Nematodes and ground pearls affect sandy soil centipede lawns, and can be treated with repeated applications of bait.
  • Finish up fertilization by the end of the September for turf if the weather is a little cooler. Potassium (potash, the ‘K’ in the NPK ratio), gives plants cold hardiness. If you are purchasing a commercial fertilizer, make sure that the last number is higher than the first (which is the nitrogen part of the ratio).
  • September and October are the time to spread a broadleaf herbicide on your lawn, for chickweed, dandelion and plantain. Follow directions and maintain a safe distance from waterways.



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