Published in the Contra Costa times on February 21, 2004

Q. What time of the year is best for aerating my lawn?

A. The soil under our lawns often gets heavily compacted with foot and
equipment traffic, and aerating, or removing small plugs is a very
necessary part of good lawn maintenance. Removing the plugs allows air
and water to penetrate the soil, and allows for greater uptake of
nutrients. If you have heavy soils and heavy foot traffic, you will need
to aerate several times a year, once in the spring and again in the
fall. If your lawn receives little traffic, once a year in the spring
when the grass is actively growing should be adequate. It is not a good
idea to aerate if your lawn is saturated as the equipment will compact
the soil, rather defeating the purpose of aerating in the first place.
If you have thick thatch layer, you should remove that prior to
aerating. De-thatching mowers can be rented, or for a small lawn, use a
thatching rake.  Complete lawn care information is available on the UC
IPM website:  http://www.ipm.ucdavis.edu/TOOLS/TURF/

My garden has been invaded by a plant that looks like carrot, but it
makes little brown seeds that spread all over the place.

The sample you brought into the office is Torilis arvensis, a member of
the APIACEAE  or Carrot family, that has become a tenacious weed in many
areas. The annual plant has deceptively ferny, delicate foliage, and a
long tap root. Small, white flowers will appear later this spring, held
in clusters above the foliage. Brown, bur-like seed heads will follow.
It is known as Hedge parsley, and has some history as an edible plant.
Deer will eat it in Britain, but do not seem to have discovered a liking
for it here.  This European native has become a pest, and as you have
found, once it has seeded, it germinates prolifically. This is the best
time of the year to weed this plant out. Hand pulling is most
successful. With the reserves found in the long tap-root, hoeing off the
top will not kill the plant. The young plants can be composted. A good
picture of the plant can be seen at
http://www.coestatepark.com/torilis_arvensis.htm.