Experts tackle readers’ garden questions.
Q: I have planted impatiens, calibrachoa, vinca and other plants in different parts of my yard. I usually use Miracle-Gro when planting in the ground. They do so well, then one by one, they start to wither and die. Can you help me with this problem? I love gardening, but I do get discouraged at times.
Master gardener Annie Kempees: The product you use is an inorganic fertilizer that is fast acting and is considered to be higher in salts. Having stated that, many salts are essential for plant growth, but excess salts in soil may be detrimental to plant health, especially seedlings, transplants and salt-sensitive plants.
When certain types of fertilizers are used, the soil pH may increase to the extent that certain nutrients become unavailable to roots of newly planted plants.
Additionally, water absorption is less effective. Over the long term, soil fertility and health may decrease as damage to worms, fungi and other microorganisms present in soil disappear.
If you choose to add fertilizer each time you plant 4-inch to 1-gallon containers, dig a shallow wide hole, add a generous pinch of fertilizer and mix it well with the soil you have just removed for the hole. This minimizes over-fertilization and death of new plants.
Remove each plant from its container, loosen the roots and gently rough up the sides of the root ball before placing it into the hole with your other plants, scoop the soil around each new plant, tamping down around the plant as you fill the hole to remove any air pockets.
Finish filling the hole until all the plants sit about 1/2 to 3/4 inch above the surrounding soil surface. Water well with a sprinkler-type nozzle.
In addition to nutrients, appropriate water and sun exposure are essential. Verify that you are meeting the needs of each variety of annual.
New plants, especially 4-inch seedlings, have a very small root system. So it is important to make sure that the small root ball is getting sufficient water, especially during hot weather.
Also, downy mildew devastated impatiens plants last summer in our area. New Guinea impatiens are not susceptible.
Annie Kempees is a University of California Cooperative Extension master gardener for Sacramento County.
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