There's lots of joy among gardeners this first weekend of March. Readers who survived on supermarket produce since Christmas will be starting seeds indoors this weekend in expectation of planting seedling plants over the Palm Sunday weekend just three weeks from now. Others will be launching a few egg cartons of annual and perennial seeds to have that long-awaited jump on the neighbors.
But the best news is the survival of your indoor plants during the winter. Not only have they weathered the worst growing conditions, but they also have resumed growing over the past two weeks while you were tending to your trees outside. The work schedule this weekend and next week reflects this kindred spirit with plants.
Begin by sorting out the winners and losers. Not all plants have survived the winter in the best of condition, so discard those that still have problems. Better to trash them now and bring in healthy replacements.
Healthy plants will need all your tender, loving care, starting with an inspection of all pots and roots to determine if repotting is needed.
Begin by turning the plant on its side and inspecting the drainage holes. In most cases, you'll find no evidence of roots coming through the holes, so give these plants only a light application of new soil to support plant growth for the next 12 months. If roots are exiting the holes or appear to cover the holes, plan on repotting immediately.
In repotting, move up to the next largest size plastic pot; if the pot now measures six inches, move to an eight-inch pot. Bang the base of the pot and the plant will come out. If the soil is dry, the plant will come out in one piece; if the soil is moist, most of the soil will remain in the pot when the plant comes out, roots and all. With small plants, both methods are practical.
When repotting plants in pots that are more than 12 inches in diameter, it is best to remove as much of the old soil as possible. Here is that scenario:
Begin by marking the plant's "trunk" with a crayon or Band-Aid at the point where the trunk meets the soil in the pot. When replanting, the plant will be planted to the same depth as it was in the old pot.
Fill a large container (a clean trash can, for example) with 12 inches of lukewarm water, then immerse your monster plant, pot and all, in the water. Rotate the trunk up and down, side to side, so it is freed from the old pot and the old soil washes from the roots. No roots will be lost, only the old soil. Remove the plant from the water and transplant immediately.
Have everything ready. The new container (plastic, of course) should have a diameter two or more inches greater than the old pot. Scatter clay shards or stones at the base of the new pot for improved drainage.
For most plants, the standard 1-1-1 formula is perfect. This means equal amounts of "milled" or compressed Canadian sphagnum peat moss, perlite and vermiculite. The peat moss functions as your reservoir, holding nine times its weight in water, vermiculite holds the food supply and perlite provides perfect drainage so oxygen returns immediately after water or water-soluble plant food has been applied.
Mix the 1-1-1 formula without water in a large plastic dishpan. Once homogenized, add hot water. Spoon off the wet mixture with your hands to a few sheets of newspaper on the kitchen counter so the soil surface dries. This mixture has a pH around 3.7 to 4, so add pulverized limestone to the wet soil as you pot it. Add a teaspoon or two of lime to the soil when you fill the pot of small plants; use a tablespoon of lime for plants in 12-inch or larger containers. Fill the pot halfway with the 1-1-1, then stand the plant in the pot and check the crayon mark on the trunk. You may have to add or subtract soil so the mark is just below the pot's rim.
Once the roots are spread out, work the soil over and around all the roots. Keep adding soil to the pot, but continue working the soil into the center of the pot so all roots are immersed and covered with soil. This is the one transplanting step that can't be hurried or omitted; the more time spent "massaging" the soil around the roots, the more spectacular will be the performance of the plant. Finally, top with soil, then apply warm water to flush the air pockets from the soil. Let the plant stand for 15 to 20 minutes to drain fully before returning it to its former location.
A footnote: If you are repotting acid-soil plants (citrus and gardenia, for example), cut the lime application in half.
Your plant inspection will probably show that most plants will not need repotting now, in which case your job has been substantially simplified. With plants that are not repotted, here is the scenario:
Mix a batch of the 1-1-1, wet it down and add lime as needed.
Water all your plants in the sink or tub. A minute later, use an old tablespoon and remove the top inch or two of old soil; it will spoon off easily with no damage to the plant. Immediately after, spoon in fresh 1-1-1 soil to fill the pot, then apply warm water again to remove air pockets. Let plants drain 15 to 20 minutes, then return them to their trays or saucers.
A footnote: if you improve the soil of your plant, and the plant has bad soil instead of the 1-1-1, you should get rid of the old soil, clean the old pot, then pot with your 1-1-1 formula. If you don't do this, you would be layering good soil (your 1-1-1) on top of poor soil, and this compromises plant performance at the start. Layering is a liability, no matter where it happens.
Having improved the soil,, return to the spring-summer care program for your plants. With few exceptions (such as citrus plants or fruiting fig trees), all plants should be moved out of direct sunlight by the March 19-20 weekend, moved away from windows or behind a curtain.
Here are some capsule care programs for the popular plants:
African Violet: Bright indirect light. Let the soil at the top of the pot go dry one day, then wet the soil. Use Peters' 12-36-14 African Violet Special at half-strength, applying to the soil in place of water, feed continually until Halloween, moving the plant back into full sun at the same time.
Spider Plant: Keep the soil lightly moist from here on, fertilize monthly year-round with 20-20-20. Bright light is adequate; never put the plant in direct sun. Allow chlorinated water to evaporate overnight before using it on plant, maintain pH around 6.6 to 6.8 at all times so fluoride in water cannot be absorbed by roots, thereby stopping burning of the tips.
Philodendron: Let the soil dry completely (10-14 days) between waterings, feed with 20-20-20 every six weeks until mid-November. Be certain to replace the soil at the top of the pot. Bright indirect light is perfect, never full sun.
Schefflera: Let the soil dry thoroughly (12-14 days) between thorough waterings. No direct sun, just bright light. Feed every six to eight weeks with 20-20-20.
Dracaena: Bright indirect light, no full sun. Keep soil lightly moist, feed monthly with 15-30-15 to Halloween, then discontinue food, maintain pH over 6.5 so fluoride in water is not absorbed by plant.
Peperomia: Bright light. Let soil dry thoroughly (two weeks or longer) between waterings. Feed monthly with 20-20-20 up to Halloween, but no food thereafter. Jack Eden hosts "Over the Garden Fence" Sundays from 10 a.m. to 1 p.m. on WTOP Radio (1500 AM).