Record Rainfall and Resilient Vegetable Gardens

More than 63 inches of rain has fallen so far this year on the Baltimore/Washington region, breaking a 129 year record. Gardeners are more often in the habit of hoping and praying for rain during hot, dry spells. This year we shook our heads in wonder as buckets of rain repeatedly pelted our gardens.

Climate change has already begun to increase yearly rainfall in Maryland. The NOAA State Climate Report (data through 2014) shows that “annual precipitation has been above average for the last two decades. The annual number of extreme precipitation events (days with more than 2 inches) averaged 2.5 days per year during 2005-2014 compared to 1.8 days per year during 1950-2004.” Scientists expect a 5-10% increase in Maryland’s annual precipitation by 2050.

Saturated Soil

Vegetable crops may recover from a24-48 hr. period in saturated soil
(where water replaces air in pore spaces). Photo credit: Wisconsin Horticulture

Resiliency is defined as “the capacity to recover quickly from difficulties; toughness.” Farmers, gardeners, and researchers are looking for practices and strategies that reduce greenhouse gas emissions and help us adapt food production to the rapidly changing environment. What makes this so challenging is that in addition to rising average temperature and precipitation we will have more unusual weather and extreme events, including drought! So what can gardeners do to improve garden resiliency in the face of excess rainfall?

  1. Move your garden location if most or all of your garden consistently has standing water in it eight hours after a heavy rain. Saturated soil deprives plant roots of oxygen and causes denitrification- the loss of soil nitrogen as nitrous oxide.
  2. Keep garden beds perfectly level and covered with plants, mulch, or cover crops to reduce soil erosion and nutrient run-off.
  3. Loosen compacted areas that stay wet with a garden fork (drive the fork into the soil and rock it back and forth).
  4. Is water flowing into your garden from the land above it? If yes, is there anything you can do to re-direct the water around your garden? Many neighbors had difficult conversations this year about the yard-to-yard movement of water, and the effects on landscapes and gardens at the bottom of the hill, or swale, or alley. We’re quickly learning that even minor land management actions can affect our neighbors.
  5. Keep soggy footpaths mulched and plant in deep raised beds filled with well-drained soil and compost. Add compost regularly to improve soil fertility and drainage. (Of course, raised beds and containers will require close attention and more frequent watering during dry periods.)
  6. Don’t fertilize all at once before or at planting. Instead, follow the 4Rs of fertilizing: right fertilizer, right amount, right time, and right place.
  7. Excessive rainfall and cloudy days can also encourage plant diseases, limit pollinator activity, and reduce produce quality and yields- even if your soil drains perfectly. Select disease-resistant cultivars, and space and prune plants to allow leaves to dry as quickly as possible.
  8. Keep planting seeds and transplants! Pull out stressed and dying plants and replace them quickly.

 

Zucchini in 15-gallon bags

Zucchini in 15-gallon fabric bags growing in a well-drained growing medium. Raised beds, bags, and containers are great tools for increasing rooting depth and protecting plants from excessively wet soils.  Photo credit: Connie Bowers

 

Pot gardening

Become a pot gardener. These herb and pepper plants (Thai and Scotch Bonnet) are
growing abundantly against a northwest facing brick wall. Dump out water from saucers
during extended wet periods and make sure the drainage holes don’t clog. Photo credit: Jon Traunfeld

By Jon Traunfeld, Extension Specialist

 

References:

HGIC’s Climate Change and Gardening page has information and resources, including a Cornell University website (click “How is Climate Change Affecting Your County?”) that shows temperature and precipitation changes over the past 63 years.

  1. Flooding, Waterlogged Soils, and Effects on Vegetable Crops blog post. University of Delaware.
  2. Safely Using Produce from Flooded Gardens. Wisconsin Horticulture. UWE.

 

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