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Because of all the watering you need to do with container plants, nutrients leach out pretty fast. As a general rule, fertilize regularly from spring through summer when the plants are actively growing, every two weeks. Stop in late autumn and winter. If you are using potting soil that contains nutrients, begin fertilizing 4 to 6 weeks after planting. But if it is not "enriched", begin fertilizing right away. You can buy fertilizer in three forms-dry, liquid, and timed release. Both dry and timed release fertilizers release nutrients over a longer period of time, so you apply them less often. When using dry, make sure the soil is wet, otherwise the fertilizer can burn the roots and foliage. If you apply too much, you can leach it out with water. Be sure the fertilizer you buy has trace elements as well as a balance of nitrogen, phosphorous, and potassium. Complete fertilizers include nitrogen (N), phosphorus (P), and potassium (K). The ratio of these three are given on the package label, such as 5-10-10 or 16-10-4. High nitrogen fertilizers (the first number in the ratio) encourages lush leaf growth. High phosphorus fertilizers encourage plants to develop strong roots and prolific bloom. Beware of over-fertilizing. I think of these high potency fertilizers as "steroids". If your soil mix is good to start with, a mix of fish emulsion and seaweed is adequate. I'm an organic type person, so I mix up my own compost tea, comfrey or stinging nettles tea, and I buy fish emulsion.

Pruning and Training

General tips:

  • All pruning cuts should be made just above some part that will continue to grow—a leaf with a dormant bud or a dormant bud on a stem. Cutting too high above will cause that part of the plant to die out and offers an entry point for disease to enter.
  • It is also important that cuts heal quickly, so use sharp clean tools for cutting.
  • Pinching back: Do it while plants are still young. Use your thumb and forefinger to nip off the tender growing tip at the stem just above the next set of leaves. Once you do this, the plant is forced to put out side shoots, resulting in a bushy compact plant.
  • Cutting back: Perennials, especially the woody ones such as sages, lavenders, and thymes, need to be cut back for best blooms the following year. Cut back 1/3 to 2/3 their length when the last flowers bloom in summer. Often this will encourage a second growth. Cut back again in late fall unless severe pruning will weaken the plant's winter survival. These you can cut back in the spring as soon as you see new growth appear. You may need to thin some plants to open up the branches and to clear out old, weak, unproductive growth. Do this when the plant is dormant.