Spring and summer, 2015… Hot and dry! The whole west coast of North America has been deprived of our spring rainfall and exposed to really unusual heat. From California’s record breaking drought right up to Haida Gwaii, there has been less than one millimeter of rain from March to July. Climatologists tell us that this is all part of a pattern and that gardening in an El Niño year is just something we have to put up with. But how does the unusual weather affect our gardens?
1. Germination. Most seeds need to be planted quite close to the surface of the soil. In a typical spring, rainfall keeps the soil evenly moist. Rain filters deeply into the soil so that even when the surface appears dry, there is moisture beneath. When the surface of soil is exposed to unusually high temperatures it will form a crust. It can actually act as a sponge and draw moisture from seeds. This is particularly true with pelleted seeds – the clay coating of each seed will suck moisture out of the seed itself unless the seed bed is kept constantly damp.
2. Irrigation. When there’s no rain, we simply have to use more of the water supply to keep our gardens alive. The drought is so severe in California this year that even farms are under intense water restrictions. Whole communities are on rotating water rationing, as the water supply is simply cut off. We need to water mindfully this season, and follow Good Watering Practice. As never before, the preciousness of water is obvious this year. Please use it sensibly. Water early in the day whenever possible, and water deeply, allowing the soil to act as a reservoir. Keep soil in container gardens generously damp. When possible, use Drip Irrigation to conserve water in the garden.
3. Bolting. This is the term to describe the sudden change from foliar growth to flower formation in many garden plants. Cilantro, arugula, lettuce, spinach, mustard, kale, and a host of other garden herbs and vegetables are prone to bolting. In just a matter of days, a plant can send up a flower stalk and become nearly inedible. This is a natural reaction to heat stress. From the plant’s perspective, hot soil indicates that summer has arrived. The plant responds by urgently producing flowers and, hopefully, seeds in order to pass on its genetic lineage. Bolt resistant varieties may not go to seed until weeks later, but all plants will eventually bloom.
4. Lack of flower formation. The tropical heat we have been experiencing causes other plants, by their nature, to grow lush, abundant foliage, but few flowers. Tomato growers are seeing excess leaf growth this season, while flower formation is weak. Garden flowers like nasturtiums are growing huge, but not forming flowers at all. Spike forming flowers like foxgloves and lupines fade suddenly from the bottom up as the plants deal with the heat and drought.
5. Early blooming. At the time of writing, it is still June. Yet there are many plants in full bloom that one normally associates with the height of summer. Echinacea, Rudbeckia, and Crocosmia flowers can be spotted in gardens all over the place, a good twenty to thirty days earlier than normal. The strawberry picking season (already at an end!) was weeks earlier than expected.
6. Sun Scald. We have already heard from pepper growers that some fruits are showing brown patches, all appearing on the same side of the plant. Normally, we don’t see peppers ripening until July or August, but once again, this is an unusual year. If you have a greenhouse, it may be a good idea to invest in some shade cloth and ventilation in order to minimize damage to fruits and vegetables. The plants simply cannot cope with the excessive heat.
More problems may occur as the season unfolds, but now just one week into summer, the results are in. A lot of gardeners are facing serious challenges this year. The National Oceanographic Atmospheric Administration (NOAA) is predicting a 90% chance that El Niño conditions will extend through this fall, and an 85% chance that it will last through the winter into 2016. What this means for growers and gardeners on the Pacific coast remains to be seen. But one conclusion is clear: We have never faced a more important time to be conservative with water.
