How To Kill Diseases In Raised Garden Beds

Diseased cucumbers — Creative Commons photo courtesy of WOODLEYWONDERWORKS.

In many parts of the country, fungal diseases are a big problem for gardeners. This is especially true when they take hold in closed environments such as greenhouses or in new transplants that are vulnerable and may be killed by an infestation.

Avoiding fungi is the best way to keep your garden disease free. Here are some ideas for doing just that.

Use Raised Beds

Raised beds have two big advantages to in-ground planting. They have better drainage so they do not hold too much water for too long, which can easily lead to fungal growth. They are also higher off the ground and so usually get better air circulation which inhibits fungal spores from starting. Gardeners, of course, know that these are just two of the many advantages to growing in raised beds.

Water Properly

Watering close to the ground via soaker or drip hose is preferable to broadcast water (sprinklers) and, in most cases, to flooding. Watering in the morning rather than evening allows the water to soak in and the topsoil to dry out, leaving enough water in the subsoil to sustain the plants, but keeping the air around the plants less humid and thus less likely to harbor fungi.

Very few plants require watering directly onto the leaves and, in fact, nearly all plants are worse off when this is the method employed. Broadcast watering wastes water to the atmosphere, can cause leaves to burn when the sun suddenly dries the water from them, and is generally much less efficient than watering on the ground.

Use Compost

Compost has a lot of advantages for the garden beyond just adding nutrients to the soil, which it is best for. Compost also adds organic matter to the soil which facilitates better drainage so that water doesn't pool and encourage fungal growth.

Select Correct Varieties

Most common garden plants have varieties that are disease-resistant, and those more susceptible to fungal infection often have fungus-resistant strains. Many strains of basil and roses, for instance, are specifically fungus-resistant. Using the right variety for your climate, conditions, and needs is the best way to prevent disease of any sort.

Mulch

Keeping the soil covered in mulch is good for the soil as well as the plants above it. Keeping soil and the bottoms of plants covered keeps the area dry. It helps resist mud formation during rain and watering and forces fungi to seek higher ground for development, impeding their progress. Mulch also keeps soil around the base of plants warmer and cooler during the night and day, helping regulate temperatures.

Use An Organic Fungicide

Many organic fungicide options are available for killing or preventing fungal infections. You can make some with baking soda and water to be sprayed on leaves and stems, or from organic garden soap mixes.

Protect Transplants

Transplants are particularly vulnerable to fungus and other diseases, so they should be protected. Avoid damping-off by removing infected soil and thoroughly cleaning beds before planting. Aerating soil between plantings in the greenhouse is also recommended to keep fungus from taking root.

In addition, transplants should be kept dry above the root, so watering at ground level and only to dampen (not inundate) soil is best.

Resources:
http://msue.anr.msu.edu/news/keep_fungal_diseases_away_from_vegetable_transplants
http://depts.washington.edu/hortlib/resources/resource_search.php?term=1831