In this issue:
Fall is for loosening the soil
Cutting back perennials
Fertilizing indoor plants during
winter
Mildew is reason to dump a phlox
Soil test and drainage
Loosen the soil now for better
lawns and gardens by spring
Dear Janet & Steven,
I try to keep from stomping around in my garden, but
sometimes I have no choice. As hard as I have tried to prevent it,
the soil seems very compacted.
Is it better to go after it with a fork and loosen the
soil NOW, or in the spring? (This assumes I can manage to miss the
irrigation tubing and not sabotage my marriage!) - C. -
Dear C.,
We aerate compacted lawns and gardens in fall. That way
infiltration rate, moisture level and oxygen content are better
below ground during both important root-growing seasons, fall and
early spring.
Garden fork, indispensable soil improvement tool
Use your spade-sized garden fork, just go easy. Irrigation
tubing is usually deeper than your fork's tines need to go, since
compaction from occasional foot traffic extends just one to three
inches below the surface. Work carefully, and even if some
sprinkler lines are shallow enough to be in your work zone you'll
feel them and be able to pull back before puncturing anything.
Irrigation lines might be acceptable collateral damage
If you do suspect a puncture, dig there and feel the pipe for
"wounds." Tie a bright colored cord to any nicked or pierced pipe,
leaving the end of the cord visible above ground to mark where
repairs are needed. Sprinkler lines are simple to patch, a small
price to pay to amend soil too dense for good root growth.
Don't turn the soil. Insert the tines, then lean back so the
ground "pops." You can aerate right through a mulch, or add new
mulch as you go. Walk backward as you pop the soil so you never
stand on any space you've already loosened. You'll work wonders by
forking that top layer. Moisture and soil animals will move into
the air spaces you created, extending them and distributing
soil-enriching humus throughout the bed over winter.
Cutting back perennials
We have balloon flower (Platycodon), bellflower
(Campanula) and Lamium maculatum 'Orchid Frost'
perennials. Do any of these need to be cut back in the fall? - R.
-
Dear R.,
No perennial needs to be cut back in fall. They manage
in the wild without us and, given good growing conditions, return
each spring regardless of our treatment.
However, you can cut back all of yours if you like, to tidy up
or to clear the deck and simplify fall weeding.
Another reason to cut perennials back would be to remove foliage
that hosted an insect or had leaf disease. Removing that debris
might decrease the plant's chances of developing that same problem
next year.
We often leave Lamium alone, so long as it was healthy
enough to avoid the fungus called "melting out," a common midsummer
problem for this species. Left in place, its semi-evergreen foliage
can be a plus in the late fall and early spring garden.
Short reports
Stop or reduce
fertilizer to indoor plants.
I.S. wonders how fertilizing and watering should change for a
tender hibiscus now that it's indoors to overwinter as a
houseplant.
Fertilizer does not cause growth, it simply supports a growing
plant the way vitamins benefit developing children. So fertilize
only when a plant is growing.
In winter, most plants don't grow. They sit and wait. Hibiscus
is typical. On a windowsill, it grows very slowly if at all between
October and March. So all it needs is water, applied only when it
begins to dry down. The plant may thin out, just hanging on until
days lengthen and the sun strengthens in late March. Then new
growth will appear and you can resume fertilizing.
If you keep your hibiscus under a grow light so it adds new
leaves vigorously through winter, you can continue fertilizing.
However, adjust fertilizer amount and frequency based on a
comparison between the plant's rate of growth outdoors and indoors.
If it grows half as fast indoors under lights, then cut the
fertilizer by half. .
Time to get rid of that
mildew-prone phlox?
You ask if this is the way to go, G.M., after you've tried
thinning it, moving it to a place with better air circulation, even
applying a fungicide beginning early in the summer to prevent the
infection.
A fellow panel member said it best, a few weeks ago as we
answered audience questions, "Life is too short and there are too
many wonderful plants to try, for you to put up with a loser. Dig
it up, compost that plant and move on!"
Green thumbs
up
to soil testing before you pronounce your garden to be acid or
alkaline.
Green thumbs down
to assuming drainage is good if the soil
surface doesn't puddle. Around buildings, soil is packed, then
graded to slope away. Excess water doesn't penetrate, it just runs
off. You must dig and fill a hole with water, then see if it
empties within twelve hours to know that a bed is well-drained.
Where it's well-drained, roots thrive, so plants grow best.
Originally published 10/16/04