Start Right and Prevent Bedding Plant Failures

Has this ever happened to you? Here is the scenario: You prepare the soil and then set out healthy bedding plants. Two weeks later, many of the plants are yellowed, wilted or dead. This situation can be frustrating and costly. Fortunately, there are some practices that can prevent the early death of spring plantings.

Any condition that stunts or slows the growth of a bedding plant after planting makes it more susceptible to stem and root disorders. Generically, early damage such as this is known as seedling blight or damping off. There are several fungi that are associated with the damage, including species of Rhizoctonia and Pythium. These fungi are present in most of our soils but only cause problems under certain environmental conditions.

Most cases of bedding plant and seedling death in newly established beds can be traced to the following conditions:

v Planting too soon after organic amendments have been added to the bed. Materials such as peat, manures and compost are highly recommended for use when preparing planting beds. However, when first mixed with the soil there is typically an explosion in the microscopic soil flora and fauna population, including some that cause seedling blight and damping off.

Given enough time, the microorganism population usually stabilizes, and it is safe to establish bedding plants or plant seeds. Any organic soil amendment that is not completely decomposed should be mixed with the soil, moistened and allowed to set for a minimum of three weeks before planting.

v Planting too early when the soil is cold. Growth of warm season flowers and vegetables either occurs very slowly or not at all when the soil temperature is low. This lack of growth and development makes them susceptible to stem and root rots that they would normally tolerate or resist. Though the urge to plant very early in the spring is strong, little is gained, so wait until the soil warms up.

v Planting too deeply. Avoid plunging the root ball of a bedding plant deeper than it was growing in the container. Tender stem tissue that was previously accustomed to air that is suddenly placed in contact with soil is very susceptible to the rot organisms. Extremely deep planting can also damage roots or kill roots directly.

v Mulching too heavily or piling mulch around the base of plants. The application of mulch to plant beds is encouraged, but it is possible to have too much of a good thing. Spread mulch at a depth of 2 to 3 inches on the soil surface after transplanting. Excessively deep mulching can damage or kill plants by not allowing enough oxygen to reach the roots. Also, don’t allow mulch to touch plant bases. Keep the mulch pulled a few inches away in order to help prevent crown rot.

v Note: When direct seeding, take the same precautions as when preparing beds for the establishment of bedding plants. Plant at the recommended depth and use treated seed. The fungicide that is applied to treat the seed coat helps to protect the germinating seedling through susceptible early stages of germination and growth.

Question of the Week: I have been told that I need to lime the soil in my vegetable garden. How long should I wait before it is safe to plant?

Answer: The lime of choice is dolomite or dolomitic limestone. It is slow acting, long lasting and will not damage seedlings or young plants when used as recommended. I hope that you are applying lime based upon a soil test, rather than on someone’s opinion. Don’t reapply lime unless a sample from the garden again shows the need.