Guide
Authors
Paul Larson
Laurie Vance
Deborah North
Publication Date: January 2025 |
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Cooler temperatures in October mean that you can finally spend more time in your garden. This month you can plant a wide variety of flowers, trees, cacti, cool-season vegetables, and shrubs. It is a great time as well to implement plans for mulching, water harvesting, and hardscaping projects. Annual flower seeds set in October can bring an explosion of color to your spring garden! Also, be aware of the potential for frost late in the month and, if necessary, protect or move tender plants.
Maintenance
- Warm-season flowering plants and vegetables (squash, melons and summer – not fall – harvested varieties of corn) can be removed to make room for cool-season ones. Consider adding them to your compost if not diseased.
- Do not perform major pruning on trees or shrubs unless plants are very leggy, unsafe or intruding on walkways as outlined in Pruning Deciduous Shade Trees. Protect newly-planted citrus from low temperatures.
- Prune roses lightly if you did not perform this task in September. Remove weak or spindly canes which are less than pencil-sized in thickness. The major annual rose pruning is recommended for mid-January to mid-February.
- Ensure you have frost cloth ready to avoid being caught off guard by a sudden freeze warning. Use it to protect cold-sensitive plants. Be aware of your plants' frost sensitivity and how cold it gets in various parts of your yard to be prepared to cover them when necessary. The article Frost Protection has more information.
- When temperatures begin to dip, bring frost-sensitive potted succulents indoors, including all adeniums and pachypodiums, and certain euphorbias. Give them a sunny spot until nighttime temperatures reach the mid-50’s.
- Mulching (3 inches or more) helps your plants withstand the colder temperatures coming later in the month. Keep the mulch a few inches away from the trunks.
- Plan and implement hardscaping & water harvesting projects while the temperatures are cooler. Harvesting Rainwater for Landscape Use and Landscape Management Practices to Optimize Passive Rainwater Harvesting and Plant Health have more information.
- If you notice powdery mildew, no treatment is recommended as it comes and goes as temperatures fall. If it’s on aged plants, remove and trash the plant (not compost it). Soft bodied pests indicate an annual plant is at the end of its life.
- Although turfgrasses are highly water-intensive, if you have them, overseed your Bermudagrass with annual rye or other winter grasses once the daytime temperatures are < 90 ⁰F and it is in the 60s overnight. Be sure to cut your Bermudagrass short before overseeding. For more information, read Overseeding Winter Grasses into Bermudagrass Turf and A Turfgrass Maintenance Guide for Residential and Commercial Lawns in the Low Elevation Arizona Desert.
Planting
- Plant trees and shrubs of all types early in the month as outlined in Planting Guidelines for Container Trees and Shrubs and Pruning Newly Planted Deciduous Fruit Trees. Warm soil temperatures and cooler air temperatures combine to provide ideal conditions for the establishment of new landscape plants. Although it may seem counter-intuitive, trees in smaller 5-15-gallon containers will establish and grow faster. Select and plant trees – including citrus varieties - so that the top of the root ball is level with or slightly higher than the surrounding soil. Read Selecting, Planting, and Staking Trees to learn more.
- Early in the month sow seeds outdoors (or plant starts) of vegetables such as arugula, beets, broccoli, carrots, brussels sprouts, cabbage, cauliflower, chard, spinach, kale, lettuce, leeks, bok choy, and spinach. Ten Steps to a Successful Vegetable Garden has more information.
- By mid-month, sow from seed vegetables and herbs such as cilantro, dill, Mexican oregano, parsley, sage, rosemary and thyme.
- Plant cool-season annual flowers now so that in Spring they will flower. Examples are petunias, penstemon, snapdragons, violets, alyssum, dianthus, and calendulas. Read the Flower Planting Guide for the Low Desert to learn more.
- Plant perennials such as Angelita and Blackfoot daisies, black dalea, desert mallow, evening primrose, germander, Mexican honeysuckle, penstemon species, red justicia, Russian sage, salvia species and verbena.
- Soil temperatures remain warm enough to plant or transplant cacti and succulents into the ground. Winter transplants experience delayed root growth due to cool soil. To learn more, read Selecting and Planting a Saguaro, How to Transplant a Cactus, and Cactus, Agave, Yucca and Ocotillo.
Fertilizing
- Fertilize roses of all varieties for the last time this calendar year.
- Fertilize new plantings of flowers and cool-season vegetables with a high-phosphorus mixture for root growth. Continue fertilizing your established flowers and vegetables. Refer to Fertilizing Home Gardens in Arizona to learn more.
- It is past time to do any citrus fertilization until the new year as outlined in the Citrus Fertilization Chart for Arizona.
Watering
- Adjust your irrigation frequencies (not length of time) for October.
- For lawns, consider shifting your irrigation start/end times as it cools to more daylight hours to prevent fungal growth.
- If you brought potted succulents indoors to protect them, water these very sparingly during this time.
- Water newly planted native and desert adapted plants (not cacti or succulents) with a gradually less-frequent schedule. Read Watering Trees and Shrubs to learn more