March 2020
by Scott Canning, Director of Horticulture and Special Projects
Last year at this time, I warned gardeners not to “jump the gun” on working in garden beds that are still wet. I thought this would be important but uncommon advice, but here again we have a wonderfully wet winter, so this bears repeating:
“The days are growing longer rapidly. We add two-and-a-quarter minutes a day of ‘sun up’ time every day in March, and when we change our clocks in March (8th in 2020), the change is that much more noticeable. Gardeners start itching to get outside and work, and that’s a great idea … but. It’s good to 
remember that we have lots of cold, possibly snowy and wet, weather ahead. Remember that we had snow in mid-May in 2019. And this March at the Santa Fe Botanical Garden, we have genuinely muddy, wet soils. It is very important not to walk on wet soils. And especially don’t turn or “work” wet soils. In late winter, soils are at their most vulnerable: They are sticky and full of beneficial air spaces from the winter’s freeze-and-thaw cycle, and will be compacted, irreversibly, by any pressure from footsteps or “work” when wet. Let soil dry to a crumbly texture before engaging in garden activity. This is common and good advice in areas of the country used to “mud season”, but these conditions are not common here, so this warning bears repeating this snowy, wet early spring.” The most vulnerable soils are our cultivated beds of ornamentals, and vegetable garden soils, so avoid those and move on to other “chores”.
Garden pruning should continue in March. Again, choose your time to be “on the soil” (if you must) carefully; using a wooden pallet or piece of plywood or even a ladder can help spread your weight, if the mud doesn’t dry quickly enough. This is the month I prefer to finish pruning any ornamental grasses that I left standing over the winter, which is most of them. I prefer a rather severe haircut, so that I don’t leave much of a collar of brown stubble from the previous years’ growth. Don’t be tempted (yet) to divide big, old clumps with dead centers; they recover better if you give those a haircut now, but wait until they begin active growth to lift and divide.
Tree pruning, like all pruning, is an art and a science. There are good reference books to help. A favorite among professional gardeners is The Pruning of Trees, Shrubs and Conifers by George E. Brown. It’s quite alright to save some money and buy a used copy; the knowledge in the field has not changed much since publication. However, there is nothing like a hands-on course. I highly recommend the course the Garden offers, “Pruning Young Fruit Trees”, taught this year by the immensely knowledgeable Linda Churchill on March 7th—or stay tuned for next year; the class fills and will probably be offered three times next year. I offer my annual class on “Pruning Roses” on April 8th.
Get a bunch of compost for the garden. If you have room to store a large pile, buy in bulk for a better deal. The compost can be spread when the beds are cut back and cleaned of debris, but wait to work the soil or “turn in” the compost until the soil dries. You can get a head-start by spreading sooner and turning in later. And good compost makes a wonderful mulch for the trees and shrubs that like enriched soils.
Annual fertilizing can be accomplished this month by using the technique of applying a ring of fertilizer and waiting to turn it in. Note that in a very windy situation (hello Eldorado!) this is NOT a good idea. I prefer organic fertilizers because they feed the soil and its myriad organisms, not just the plant, as liquid fertilizers primarily do. One caveat if you spread now and turn later: Many organic fertilizers use blood meal, bone meal and feather meal as constituents, and some dogs will find these irresistible. They shouldn’t harm your dog seriously, but a dog of mine got a very upset stomach after following me around and eating lots of ‘PlantTone’ behind my back!
As you plan for the coming season, please consider adding more native plants to your garden. Insects of all types are in decline and in need of our help, pollinators especially, and they co-evolved with native plants. I’m not a “native plant fascist”, but I am definitely leaning that way, more so each year. But I think I will always grow tomatoes! Also, we need to transition to sustainable gardens, and the day will come (inevitable next drought?) when irrigating with municipal drinking water will be prohibited or severely restricted, so try to be prepared with a garden that relies on natives, hardy succulents and drought-tolerant grasses.
Keep up with seed starting and grooming your seedlings. Grooming? I sometimes use a fan for a few minutes a day to gently flex the stems of seedlings; safer still is gently brushing your seedlings back and forth with a ruler or bamboo stake. This mechanical action toughens the stems of seedlings and helps keep them from stretching excessively, but this should be done in addition to adequate light, which is the most critical factor for compact, healthy seedlings. You can also gently shake the pots or flats of small seedling as you check on their water and general development, which should be done at least once a day. I like Margaret Roach’s A Way to Garden” for a wealth of sage seed-starting advice and week-by-week calculators.
IF your soil is ready, you can start a few short rows of cold-hardy vegetables, like arugula, spinach, kale and most of the mustard-family veggies, which are numerous, at the end of the month. And it’s time for peas soon, but NOT beans- they need warm soils!
