January Monthly Gardening Reminders

Guide
Authors
Paul Larson
Laurie Vance
Deborah North
Publication Date: January 2025

Sunny days, with average highs in the mid-60s and lows in the 40s, mean that Tucson desert dwellers and those in the low desert have a unique opportunity to garden in January while the rest of the nation is largely covered in a blanket of snow. This pleasant weather makes it an ideal time to tackle annual maintenance or some of the more physical activities on your to-do list. Continue to keep an eye on nighttime low temperatures and protect cold-sensitive plants. Review your irrigation settings if rainfall is generous. And tell your friends in cooler climates about all the things you’re planting this month!

 

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Maintenance

  • Stay on top of garden cleanup.
  • Winter rains bring weeds – be vigilant! Suppress their germination by applying thick layers of mulch such as wood chips or straw. Regularly pull weeds as they emerge. • Do the annual check and repair of your irrigation system(s). Refer to Drip Irrigation: The Basics.
  • There are several pruning activities that are important to complete in January and February. Here are some guidelines:
    • Trim deciduous fruit trees and shrubs this month while they are dormant. Refer to Training and Pruning Newly Planted Deciduous Fruit Trees.
    • Other deciduous trees, such as Arizona ash, can also be pruned. As a minimum, remove broken or crossing branches, but never more than one-fourth of the total branch area. Refer to Pruning Deciduous Shade Trees.
    • Grapevines can be pruned now through mid-February. Follow pruning of the dormant vines with a thorough, drenching spray of horticultural oil. This is a first step in managing overwintering pests such as grape leaf skeletonizers. Refer to Growing Grapes in the Home Garden.
    • Prune established roses beginning in the middle of the month. Cut canes back by one-third to one-half, just above outward-facing buds (not those aimed toward the plant’s center). Newly planted specimens (see below) are not pruned.
  • Do not prune citrus unless branches are broken or impeding a pathway.
  • Do not prune frost-damaged plants yet. Even frozen branches will protect the plant somewhat. In mid-March when plants begin to leaf out, you will be able to tell what part of the plant is still alive. Do not prune spring-flowering plants until after they bloom.
  • Be prepared for frost and freezing temperatures: 
    • Know your USDA Plant Hardiness Zone; it helps localize your temperature expectations for plant protection. See reference link below.
    • When freezing temperatures are predicted, cover frost-sensitive plants with frost cloth or old sheets. Never use plastic. In Tucson, March 15 is considered the average date of the last frost, so do not be fooled by moderate temperatures. Refer to Frost Protection. Your last frost date may be later if you live at higher elevations or in a cold valley.
    • If a frost or freeze is forecast, cap cold-sensitive cacti, such as totem pole, golden torch, Mexican fencepost, and young saguaro. Use a paper grocery bag or large Styrofoam cup to protect the delicate growing tip from the cold. Do not use plastic in direct contact with the plant; it will conduct cold, not insulate. After the freeze, remove the cap, but keep it – you can reuse it. Refer to Problems and Pests of Agave, Aloe, Cactus and Yucca.
    • Pick exposed lemons and limes before a hard freeze. Some damage to these fruits on upper and outer portions of the tree will occur when temperatures drop to 28 degrees. Other types of citrus fruits can handle cold temperatures better. Refer to Protecting a Citrus Tree from Cold.
  • Consider planning or installing active or passive rainwater harvesting. Refer to Harvesting Rainwater for Landscape Use and Landscape Management Practices to Optimize Passive Rainwater Harvesting and Plant Health.

Planting

  • Plant bare-root deciduous fruit trees such as apple, apricot, peach, and plum trees. Refer to Training and Pruning Newly Planted Deciduous Fruit Trees and Selecting, Planting, and Staking Trees.
  • Prepare vegetable and flower beds for spring planting. Plant artichoke crowns, asparagus, cane berries, onion sets, and bare-root strawberries into the ground. Importantly, when buying strawberries or other plants as bare root (not rooted transplants, which do not get planted now) from local nurseries or big-box stores, be sure the roots are moist and viable – and that they remain that way until planted.
  • Plant seeds into the ground for vegetables such as beets, carrots, radish, leafy greens, peas, and onions, as well as cool-weather flowers such as stock, snapdragons, pansies, and alyssum.
  • Start seeds indoors for tomatoes, peppers, and eggplant. Refer to Ten Steps to a Successful Vegetable Garden.
  • Plant bare-root roses. Purchase only high-quality plants from reliable garden centers. The planting bed must be amended with organic matter such as compost, peat moss, or aged manure to a depth of 18 inches. Be sure your soil drains well and that the swollen graft union near the base of the canes is above the soil level. Refer to Rose Selection and Planting in the Low Desert.

Fertilizing

  • Continue with mild fertilizing of winter vegetables. There are various fertilizer options, including organic and chemical fertilizers. When using organic fertilizers, it's important to apply them early to allow sufficient time for breakdown, ensuring a steady nutrient supply as plants grow. Refer to Organic Fertilizers and Fertilizing Home Gardens in Arizona.
  • Bearded iris may be fertilized toward the end of the month. Scratch fertilizer into the soil near the bulbs and water in thoroughly.
  • Other uses of fertilizer are not advised. Fertilizers stimulate new growth that will be frost sensitive.

Watering

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