Puttering with Pots!
from the Davis Enterprise, August 24, 2006
Why
use containers?
á You can garden in small
spaces, or create spots of color in otherwise boring landscapes.
á Perhaps youŐre a hobbyist
or collector--I like the term "plant enthusiast.Ó Pots enable you to
provide for the special needs of
certain plants.
á You bought something on a
whim? Something with special needs? Been there, done thatÉ. Many of our
favorite plants need special fertilizers, winter protection. Containers give us
more flexibility about soil and location.
á It can reduce garden-related
stress: putting together a color bowl can be a quick, easy project providing an
immediate sense of completion in our busy lives!
á A landscape project seems
overwhelming to your child, but putting together a container garden is a simple
activity that you can do together. It's perfectly in scale with their size and
aspirations.
á Gardening in containers
gives immediate results, and can be an easy way to get color or greenery during
very hot or cold, dreary days.
Learning
how to make plants live and thrive in pots simply increases your satisfaction.
So here are some basics.
Which
type of container is "best?"
á Plastic is lightweight,
portable, and cheap. It doesn't "breathe", so plastic pots tend to
need less frequent watering. Downside: they donŐt provide enough weight to
anchor a top-heavy plant.
á Clay is durable, but
breakable. It does breathe, and it tends to accumulate salts in areas with hard
water. Clay pots vary from lower-quality Mexican pots, which last a couple of
years, to harder-fired Italian pots, all the way up to dense glazed ceramic
pots.
á Wood ages gracefully and
is long-lasting. Well-made redwood planters can last for decades. Oak barrels
are very economical, and last for several years if they are never allowed to
dry out.
What
potting soil should you use?
á Quality varies, and you do
get what you pay for. Inexpensive blends often contain shavings or other
materials that arenŐt fully composted. As these break down, harmless fungus
will grow on them—and fungus gnats will happily dwell on the fungus.
These are the little black flies that flutter aimlessly around your plants. Not
harmful to the plant, but annoying and often a sign that you may be
overwatering.
á A good quality potting
soil is a blend of compost, sand, and peat moss, and may have other additives
such as fertilizer (organic or chemical), and pumice, bark, or perlite for
drainage. It should drain quickly but retain moisture.
á Most additives donŐt
encourage diseases, so potting soils don't need to be sterilized. Using compost
or soil from your own garden isnŐt recommended, as these can be sources of
weeds or pests. You can sterilize garden dirt in the oven, but it smells
really, really bad (IŐm speaking from experience hereÉ).
á Special soils for certain
plantsÉmost of the special blends simply vary the basic ingredients to increase
drainage, or adjust the pH. Cactus, bonsai, African violets, ferns, orchids are
all examples of plants which need faster draining soil. Plants that get big and
heavy can tip over if the mix is too light, so cactus, succulents, and trees
may be grown in a mix that has more sand to increase the weight.
What
do container plants need?
There
are four things all plants need to grow--air, light, water, and nutrients. What
made Aunt Nellie seem like a successful gardener was that she knew how her
individual plants varied about these needs. Container plants are more
vulnerable and more sensitive because theyŐre confined. But itŐs how we provide
these basics that lead to success.
We
can't do much about air! Ok, keep your pots out of strong winds, as container
soils dry out quickly. The other three--light, water, and nutrients--are within
our control.
Remember:
a plant in the ground has a reservoir of water and nutrients nearby that the
roots can seek and draw fromÉ.in a container YOU are providing ALL of the water
and food!
á Light: How much sun or
shade are you gardening in? Container plants are easier in at least partial
shade. Some plants will take full sun: Citrus, cactus and many succulents,
kitchen herbs. Indoor light is much trickier. Most houses have about ¼ -
1/10 the light of outside. Very few flowering plants will thrive in that. Many
popular house plants such as Philodendrons and African Violets are from the
dark understory of tropical forests. Plants that arenŐt getting enough light
stretch, have paler leaves, and are more prone to rot.
Direct sun on a dark container cooks roots! The
temperature of the soil on the west side of a nursery pot is lethal. Shade the
pots, paint them, set them inside larger pots – do whatever it takes to
keep direct sun off the container.
á Watering is Job One with
container plants in the Sacramento Valley! The more rootbound a plant, the more
often it needs water. The bigger the pot, the longer you can go between
waterings. An oak barrel typically needs water only once or twice a week.
Anything smaller may need water daily during extremely hot weather; more
typical is every 2 – 3 days. Grouping container plants together can help
shade the pots and make watering easier.
Water-retaining polymers came on the market
several years ago. These absorb water (100x their weight!) and then release it
slowly Ôas the plant needs itŐ. But hard water significantly reduces the
effectiveness of polymers. Peat moss is natureŐs version, absorbing 10 –
15x its weight in water. But when it dries out, peat moss is very hard to
re-wet. So it shouldnŐt be more than about 1/3 of the total mix.
á Food: Most potting soils
contain enough fertilizer to last 2 – 3 months. Additional organic
fertilizers can be mixed in the soil at the time of planting. Slow-release
resin-coated types (OsmocoteŞ is the best-known) can be put on the soil surface
once a season, releasing a trickle of fertilizer with each watering. The
popular soluble fertilizers (mix and spray!) are great for flowers.
á Repotting is done every
year if you want the plant to grow bigger, or if you find itŐs so rootbound
that youŐre having to water daily. The new pot should be 2 – 4Ó in
diameter larger. Transplanting is best done during mild weather. But as long as
you provide food and water, a plant can live, very rootbound, in the same pot
for many years.
Note: most indoor plants are rootbound when you
buy them. They are often in a potting mix that is designed for the growerŐs
needs—lightweight for shipping, or for greenhouse watering systems. If
theyŐre flowering, repot them as soon as they finish. Foliage plants should
usually be repotted right away.
What
are you growing, and how long do you want it to stay in that container?
á Specimens: cycads, palms,
dracaenas, cactus and succulents are examples of plants that can stay in the
same pot for longer than a human generation! People who collect these plants
use tricks to keep them healthy and easy to care for. They usually use a
somewhat denser soil mix to accommodate the weight of the plant (this also
helps retain water and food), and find clay or ceramic pots more effective.
It's worth buying a fancy pot to show off a specimen plant.
Bonsai is a specialized container gardening skill.
Roots are pruned each year to remove ¼ - 1/3 of the total mass, then the
plant is repotted in the same (or smaller!) pot to intentionally stunt it and
develop a wizened look. Trees may be kept this way for hundreds of years. Most
bonsai are best outdoors, and are easiest to grow in partial shade. Bonsai may
need water daily in hot weather here.
á Seasonal: at the other end
of the spectrum are color bowls, which are basically flower arrangements with
roots. Check out Sunset Magazine
and you'll see these artistic groupings. Note the creative use of foliage
plants, grasses, and succulents—these are tricks to keeping the
ÔarrangementŐ looking acceptable longer than youŐll get from annual flowers
alone.
Even seasonal annual flowers are much more
satisfactory in larger containers. A barrel or large pot allows the plant to
root deeply and reach its full potential.
By the way: get ruthless with annuals! When they
look ratty, pull them and pop in some new ones! What made Aunt Nellie a
successful gardener was that she knew when a plant was done and threw it in the
compost pile!
Containers
expand our gardening options and our obligations. Most novice gardeners start
with plants in pots, which are actually trickier than plants in the ground! So
forgive yourself the occasional toasted or rotted specimen and try again.
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