Garden Help Desk: Reducing risk from disease organisms in water
Last week, we talked about some of the food safety issues related to E. coli-contaminated irrigation water — what you could or couldn’t safely do with produce that had been irrigated with unsafe water. In today’s column, we’ll be looking at ways we can reduce the risk of food safety problems with our homegrown fruits and vegetables in the future.
For gardeners in Lehi, the E. coli issue stems from pressurized irrigation water (PI) that has been contaminated with the E. coli bacteria. But PI water isn’t the only way that pathogens like E. coli, listeria and salmonella find their way into the garden. The risk of food-borne illness doesn’t mean we should be afraid of our homegrown produce, though. It just means we should be aware of the different ways we can reduce the risk and put them into practice.
Home gardeners and hobby orchardists can adopt many of the Good Agricultural Practices (GAP) recommended for commercial growers by the U.S. Department of Agriculture and state research-based organizations such as Extension Services to reduce the risk of food-borne illness from homegrown produce.
Use drip irrigation wherever possible. Keeping the foliage of plants dry is the healthiest choice for your plants because it reduces the risk of fungal and bacterial plant diseases. It’s also the healthiest choice for you because it reduces the chances of water-borne bacteria ending up on your fruits and vegetables. Inspect your drip system frequently to make sure there aren’t small leaks or poor connections where water can spray out onto your plants. If you use micro sprays, be cautious in your placement in your garden to make sure the foliage on your plants stays dry.
Mulch the garden with straw, grass clippings, clean compost, layers of newspaper or cardboard to prevent rainwater from splashing contaminated soil up onto the lower parts of plants. A single layer paper grocery bags or craft paper, or a few layers of newspaper under the mulch, will make the mulch even more effective at keeping splashed soil away from your produce. Drip irrigation emitters and hoses should be placed under the mulch, not on top.
There’s no way to avoid getting contaminated water on your root crops, but vertical gardening is another way to keep other kinds of produce clean. Trellises, nets, cages, staking, posts and fencing can all be used to keep the fruits of vining plants like melons, tomatoes, cucumbers, squash and green beans away from soil that may be contaminated. Some of these vegetables will easily climb on their own or with just a little encouragement. Others may need to be tied to their supports once or twice a week as they grow.
Avoid using fresh manure. Cows, sheep, goats and pigs can all carry E. coli or salmonella bacteria. Salmonella can also be found in the droppings of birds. With sufficient time, the pathogens in fresh manure will die. It’s fine to use any kind of manure in the garden, but it should be aged for at least one year before it’s applied to a garden.
Ideally, fruit trees wouldn’t be planted in lawns, but that is a common practice. Choose low-angle nozzles to avoid having water hit the canopies of fruit trees. A lower-angled spray is also less likely to be carried away on a breeze. Adjust sprinkler nozzles to produce a coarser spray with heavier droplets instead of a fine spray with misting that can be carried into the garden on air currents. Adjust sprinkler systems to prevent overspray into nearby gardens. All these changes will keep your plants drier and healthier while also making your landscape more water-wise.
Prune fruit trees properly each spring and thin fruit trees in the late spring to early summer to prevent branches from bending down into the path of nearby sprinklers.
Use only potable water when mixing pest- and disease-control sprays for your fruits and use potable (drinking) water, not pressurized irrigation water, when rinsing off fruits and vegetables after harvesting. Wash your hands after handling your produce.