For:
By: Daniel E. Mullins
Extension Horticulture Agent
Prepare Annual Beds Well Ahead of Planting for Best Results
Timing is everything when gardening. Even a normally successful practice, if performed at the wrong time, can result in failure. Such is the case when adding organic soil amendments to spring annual beds.
Have you ever prepared a planting bed for spring annuals and planted, only to see your plants shrivel and die after 2 or 3 weeks? This is a common problem, and one that can often be prevented just by making some minor changes in timing.
Organic materials such as peat, compost and manures are highly recommended for use when preparing to plant annual flowers, vegetables and herbs. Used properly these materials, when mixed with the existing soil, improve the moisture and nutrient holding capacity. If used improperly, these same soil enriching amendments can lead to problems.
Soil amendments vary in their stages of decomposition. The fresher, or less decomposed the material is when applied, the more likely that a problem will be experienced.
Extremely fresh organic material has an immediate impact once tilled or spaded into the soil. When introduced to the native soil there is a rapid increase in the numbers of soil flora and fauna. These soil microbes reach tremendous numbers as they help to decompose or break down the organic materials to a more usable form.
This is the soil’s natural reaction to the introduction of fresh organic material. If young plants or seeds are planted while these microbes are highly active, there is a good chance that they will experience nitrogen deficiency, root rot or seedling blights.
These microbes, known as saprophytes, are normally beneficial to the soil. It’s just that for a time following the addition of fresh organic amendments, there is an imbalance.
This imbalance affects plants in two ways. “Nitrogen robbing” is a term that is often used for one of the conditions. It simply means that the soil microbes temporarily use available soil nitrogen, converting it to protein as their numbers increase.
Plants can be seriously affected by this nitrogen robbing. Since the soil nitrogen is temporarily unavailable to plants, they can become stunted and yellow.
The phenomenon might be better called “nitrogen borrowing.” As the microbes complete the decomposition process and begin to die off, they release the nitrogen back to the soil in an organic form.
Root rots and seedling blights are also frequently the result of adding organic materials to the soil just before planting. Because of sheer numbers, these normally safe soil microbes can infect young root and stem tissue.
Avoiding such problems can be relatively easy. Continue to use organic amendments, but make sure that they are stable before planting herbaceous plants and seeds. This can be accomplished by either composting until materials are well broken down or by adding the material to the soil and waiting until this underground microbial battle is past its peak.
Gardeners are therefore advised to prepare annual beds early if fresh organic materials are used. Go ahead and add and incorporate the amendment, keep the bed moist and wait a minimum of 3 weeks before planting.
Question of the Week: The recent freeze has caused damage to some of my plants. When should these dead branches and twigs be pruned away.
Answer: Light pruning can be
done to remove brown or black twigs and branches, but wait until late winter or
early spring to do any major pruning of damaged plants. There is generally a delayed reaction to cold
damage. Pruning too soon would probably
result in either the removal of too little or too much tissue.