March Garden Checklist
By Kelly Young
WHAT TO PLANT
Arizona’s Low Elevations
Artichokes—Find transplants at your local nursery, and put them in a location where each plant can have at least 3 feet in all directions to grow. Plant crowns or transplants
18 inches apart in rows, with each row 2 to 3 feet apart. Artichokes require consistent soil moisture. Water frequently to ensure root and shoot growth.
Cool-season vegetables—This is the last chance of the season to plant beets, green onions, carrots and mustard greens from seed. Select varieties that will be ready to harvest in fewer than 45 days.
Warm-season vegetables—Plant seeds of cucumbers, melons, squash, bush beans, peppers and eggplant, and promptly cover seed beds with floating row covers. Available at most garden centers, floating row covers protect emerging seedlings from birds and other pests, such as whiteflies.
Ornamental trees and shrubs—Place greenery in a permanent location that offers ample room for the plant to grow unimpeded by buildings or other structures. Select plants that have no visible signs of damage or circling roots. Dig the planting hole no deeper than the depth of the root ball. Discard the nursery stake. Stake trees that do not stand up on their own; use at least two stakes.
Perennial grasses—These landscape workhorses require very little supplemental water or maintenance to look great. Look for pink muhly (Muhlenbergia capillaris) and blue grama (Bouteloua gracilis) for low-maintenance pops of color.
Arizona’s Middle Elevations
Cool-season vegetables—Sow chard, kale, beet, cabbage and carrot seeds in a bed enriched with compost. Plant large garlic cloves (1- to 1.5-inches tall) pointed side up, 2 to 3 inches below the soil surface and 6 inches apart.
Fruit trees and vines—Consult your local garden center or nursery for apple, pear and stone fruits that are proven to perform well at your elevation. Keep in mind that you may need to plant more than one cultivar; some, such as sweet cherries, require cross-pollination for successful fruit production.
Woody perennials—Plant trees, shrubs and vines now, but protect them with frost cloth if nighttime temperatures are colder than usual. Space providing, consider planting in groups of at least three for better visual appeal.
Arizona’s High Elevations
Vegetables—Plant root vegetables and seeds of leafy greens outdoors. Start warm-season tomatoes, peppers and cucumbers indoors now for transplanting in May.
Warm-season vegetables—Sow seeds of sweet corn and cucurbits, such as cucumbers, cantaloupe, honeydew, watermelon and squash, once nighttime temperatures have consistently warmed to at least 65 degrees. Transplant varieties now so they have time to set fruit before warm spring temperatures become the norm.
PRO TIPS: CITRUS
By Kevin Erdmann, Certified Arizona Nursery Professional and Master Gardener, Berridge Nurseries
- When shopping for citrus trees, look for those that are evenly branched with few to zero dead twigs. n Full-sized trees require a 20-foot circumference canopy; allow a 10-foot circumference canopy for dwarf varieties.
- Plant so the topmost roots are just barely covered; trees buried too deeply will not survive.
- Protect trunks that are exposed to direct sun by applying white or tan tree paint or a tree wrap.
- Regardless of your new tree’s size, do not expect fruit for the first three to four years on full-size citrus; dwarf trees will not bear fruit for one to two years.
Arizona’s High Elevations
Adjust irrigation—Plant water needs increase as days get longer and warmer. Irrigate more often and always to the appropriate depth: 1 foot for vegetables and other annuals, 2 feet for shrubs and 3 feet for trees.
Arizona’s Low Elevations
Give pollinators safe haven—For better pollination of summer crops, make sure your garden is filled with flowering plants. Even blooming weeds can be excellent sources of pollen and nectar for foraging bees. If you must spray your landscape for insect pests, do so in the evening, after bees have gone to sleep.
Harvest cool-season vegetables—Pick onions, beets, carrots and other rootlike vegetables once they’ve reached an acceptable size for consuming. Make room for warm-season crops, and cull any plants that harbor significant populations of aphids or other insect pests.
Fertilize citrus trees—If you didn’t do so in February, provide trees with one-third of annual nitrogen required. Download the Citrus Fertilization Chart for Arizona at extension.arizona.edu to determine how much fertilizer to apply.
Prune perennials—Cut back plants that were damaged by the winter’s freeze, have outgrown their space or are unattractive. Tree branches should always be cut back to their point of attachment. Never leave a stub on trees because the stub will die and create an easy entry for pests.
Arizona’s Middle and High Elevations
Protect frost-sensitive plants—Cover young seedlings and recent transplants with frost cloth at night when temperatures dip below 32 degrees.
Fertilize—Support new growth in deciduous trees, shrubs and vines with a boost of nitrogen.
Is there any way to prevent cucumber beetles from ruining my garden? These pests were so bad last year that I had to abandon my beds.
Once cucumber beetles discover a location where they can reliably find their favorite foods, they will visit year after year. True to their name, cucumber beetles love cucumbers and other cucurbits, including melons and squash. According to Tucson-based entomologist Peter Warren, adult cucumber beetles feed on leaves and flowers, while the larvae prefer the roots and stems. Damage isn’t caused by the insects’ feeding alone; they also transmit bacterial wilt, which causes the rapid collapse of the plant. Consider taking a break from cucumbers and their kin this planting season. Depriving the beetles of their favorite food source is one of the best ways to reduce their numbers in the future.
Can I compost coffee filters? I know it’s okay to use the coffee grounds, but will the paper filters decompose, too?
It depends. Paper coffee filters are compostable, but they may not decompose very quickly if added to the pile straight from the machine. Larger items tend to break down slowly, so you might consider cutting the filters into smaller pieces before adding them to the pile. Once you have created a pile that is approximately 3 feet high, wide and deep, stop adding materials to it, as this will further slow the process.
Our son and daughter-in-law are expecting their first child (and our first grandchild), and to commemorate this joyful occasion, we would like to give them a tree to plant. They just moved into a home with a large yard in Mesa, and the landscape is pretty barren. What type of tree do you recommend?
Congratulations on becoming grandparents. Planting a tree is a beautiful way to celebrate a special occasion and add value to a home at the same time. I recommend letting the new parents select from the Arizona Municipal Water User’s Association’s list of 44 trees that are proven to do well in the low desert (amwua.org/plants/trees.php). They can filter the options by the mature size of the tree and the amount to light exposure it will receive. To make the gift even better, throw in an irrigation timer and soaker hose. Adequate irrigation is critical to establishing a healthy tree that the family will enjoy for decades to come.