a.g.
When
I plant new plants in the yard, there is always
some soil that comes out of the hole that doesn't
fit back in. I tend to use that in Outdoor pots.
As far as the pots are concerned, what should be
added for healthy containers?
RA
Garden
soils is usually too heavy for containers, so you
do really need to lighten it up. For some plants
you run the risk of soil born pathogens, so I wouldn't
advise doing this for seeds or plants like Rhodies,
azaleas, daphne or any others prone to water molds,
but for most plants it should be o.k. Any inorganic
amendment like coarse sand, vermiculite or perlite
along with an organic component like peat or round
bark in more or less equal measure should work fine
-- perhaps more of the
coarse stuff if you soil is at all heavy. You want
and end product that is friable and drains well.
judi
z.
Assuming
the soil is basically decent, what annual topdressing
care should be taken? What basic soil amendments
should be added annually? I topdress with compost,
manure (well-aged, of course) and greensand, but
I know there are other micronutrients that might
be helpful.
RA
I
don't think I would advise regular applications
of many products without knowing what your soils
is already rich and/or deficient in. You can end
up playing junior
alchemist if you get going too much, and if you
end up with an excess of one nutrient, you can end
up tying up others. Even that greensand could gradually
build up potassium levels too high over the years,
though potassium is very slow to translocate.
Right offhand, though, ytou might add a little gypsum
once and a while, or else lime if your soil is acidic.
Donna
Lockman
Can
someone define green sand? Also I have been told
not to add sand to my clay that it will make it
harden like cement!?
RA
Greensand is dredged from the ocean floor and then
rinsed to remove the salts and is somewhat similar
to diatomacious earth. It is rich in potassium silicates
as well as other nutrients.
In general, sand added directly to clay and you
can end up with something approaching cement unless
you have suitable organic matter, in which case
it is o.k. If you add lots and lots of the organic
matter first, some extra sand is fine.
RoseNC
What
about composted cow manure? Can I topdress around
plants with that? OR is it better to work it into
the soil?
RA
Most
plants like manure, but the disolved salts can be
a bit much for some that are salt sensitive like
ericaceous plants. Depending on its age, it's also
good to keep it a bit away from the crowns of the
plants, but it's fine as a topdress.
Joaniesgarden
Instead of the standard peat moss as a soil amendment
in containers this year I was going to try Coir...I've
bought 5 big bricks of it, what do you suggest I
mix with it for thirsty containers?
RA
I
love coir and find It holds a surprising amount
of water -- perhaps not as much as the peat, but
without some of the problems associated with peat
like the inability of
peat to regain moisture after going dry . If you
are really worried about water, you could always
add some of those water retaining polymers, but
other than that you
should be fine.
judi
z.
Home
soil testing kits: Are they somewhat accurate? Misleading?
Some good, some bad? I haven't had a soil test in
some years, leading me to believe it's time. Is
it better to send samples to my local county extension
agent?
RA
I
think it's better to send one in vs. doing a home
test. The home kits can be fairly accurate, but
won't reveal as much info or be as precise. With
either, though, it is
important to take good samples, and make sure you
get representative soils. Best to take them from
areas not recently fertilized, such as those marginal
garden spots.
Donna
Lockman (follow-up)
Richard,
Say I go out to take a soil sample or two, with
trowel and small boxes or bags? Do I just dig a
trowel full and place in bag, or do I dig up the
area first and
then get a trowel of dirt for the bag?
RA
If it is a regularly maintained garden bed, I'd
suggest digging down a few inches rather than using
the stuff right off the top, and to do so from a
few different areas.
The mulching and fertilizing you have done will
affect the surface more than down lower and taking
from different areas will even out some of the anomalous
readings and give you a better picture.
If this is from an unprepared area, you don't need
to be as picky, but it still helps to get different
samples.
One thing I didn't mention to Judi, but if you send
in a sample rather than home test, you can get recommendations
for what to do if something is deficient or out
of whack.
Donna
Lockman
I
dug my daylily bed, added compost and gypsum and
then around each plant, I placed a handful of bone
meal. I top dress spring with compost and fall with
fine mulch. Things do great there. My problem is
an iris bed that is so rocky it is like a quarry.
I am constantly removing rock from that bed. Iris
like drainage and the rocky ground seems to agree
with them. The lower part of the bed is so rocky
however, that the iris can't walk or multiply easily.
I noticed that they are not blooming in that area
as much either. Now removing ALL the rock is impossible!
But if I dig all the irises and their labels from
there and put them in bags in a tub or something...then
remove as many rock as I dare! What type soil and
additives do I fill in there for the TB irises.
There are Tall phlox in back and some purple homestead
verbena in front of the irises.
RA
Iris don't need too much organic matter and like
a neutral soil, so if you have access to some reasonably
good topsoil -- a real sandy loam -- you might be
able to give
them enough to get rooted in above and around the
rocks. Now, there is sometimes a problem that can
occur when you put one type of soil right on top
of another in that
water goes through one strata of soil, hits the
next and just sits there -- despite the fact that
both might be well drained. For this reason, you
want to try to blend the new
soil with the old, if just a little bit. Other than
that, getting some phosphorous and potassium in
there ahead of time helps, since both of these nutrients
are very slow to percolate down. I'd avoid manure,
too, though something else with nitrogen in modest
amounts doesn't hurt. .
Donna
Lockman
I
have used lime on my lawn to lessen the acidity.
I have used sulfur to raise the acidity before planting
Rhododendron/Azalea and Japanese Iris. Do I reapply
this yearly or what? And am I adding the best things
for the jobs here?
RA
Sulfur
and lime are the two usually recommended for altering
one way or another, but I don't think you would
need annual applications. So much of what you do
otherwise tends to affect ph., especially if you
use lots of soil amendments, and much depends on
the plants you are growing, so it's hard to say
without knowing. Here in parts of the the pnw, liming
is a regular undertaking since rain leaches so much
and we can have such acidic soil, but I would doubt
that you would have to do so every year. If you
are using both acidifying and alkalizing agents,
your soil couldn't be too strong one direction or
the other -- probably a little acidic -- and fortunately,
a large majority of plants will grow quite happily
in a slightly acidic soil.
Joaniesgarden
In past soil tests, my regular garden soil that
has not been cultivated is around a pH of 8. My
city water is testing alkaline as well.....( I can
usually tell by all the heavy
deposits on my aquarium without testing. :-/) I
have very pale leaves on things like magnolia and
buttonbush and Virginia sweetspire...what can I
use to make the soil more acidic and have a lasting
effect without reapplying several times a season?
RA
Probably
the best thing is lots of organic matter dug into
the soil as well as a good mulch. The organic stuff
helps buffer, as well as being slightly acidic for
the most part depending on composition. Besides
using sulfur or aluminum sulfate to intentionally
acidify, you will find gypsum helps too along with
improving tilth and providing calcium.
Joaniesgarden
Which in your opinion are the best overall slow
release fertilizers for container plants? (most
things being annuals like petunias)
RA
I like Apex, and I don't know if these are available
retail or not, but there are several different formulas
with different release rates. They aren't affected
by soil moisture,
but do release faster with higher soil temps, so
as plants grow faster with warmer weather they get
more fertilizer. For annuals, which like lots of
fertilizer, this is really
helpful, and you can chose the faster releasing
formulas. Better than the one size fits all approach.
Tina
This
year I plan on adding soaker hoses to my sunniest
beds. I tend to plant things close together and
have rarely mulched these beds or had a need to.
However I don't want the hoses to be visible. Do
you have specific types of mulches you recommend
for the on-gardening season that would cover the
hoses? The soil is quite good in both these beds.
In other areas during off-gardening season I've
used the small wood chips more for appearance then
anything and like that they break down quickly into
the soil so that by the springtime I can simply
work them into the beds. This is the bagged stuff
sold at any garden center and I wonder if I could
do better off season with a more nutritional type
of mulching. Do you see a difference in the properties/benefits
of one mulch over another?
RA
Whenver
the subject of mulches comes up, people tend to
respond based on what they have available where
they live, but what matters is what's available
where you live. The large majority of commercial
mulches here in the pnw use ground fir as a base
as well as composted plant material from municipal
leaf collection and dropped off yard debris. To
these bases, they might add lime, composted mint
straw, chicken or cow manure, etc., so there tends
to be some differences depending on who's doing
it.
You should be able to find some blends where you
live that are more nitrogenous than the straight
ground bark. Mixes that have some manure in them
are very common here, and I'd think they would be
available up there too. They would do nicely, if
so.
One think about soaker hoses, though, is to not
forget to overhead water from time to time in summer.
Thrips and mites, especially, can be a big problem
where you don't overhead water.
Tina
For
those gardeners who have never tested their soil,
can you explain the benefits and the best method
of sampling? How often should it be done?
RA
It's certainly not the sort of thin you need to
do all the time.
As to the benefits, the main one is that you can
identify nutrient deficiencies as well as know you
p.h. Now, the ph is the western parts of the northwest
is usually acidic, and sometimes strongly so, but
I doubt where you live that it is so acidic as to
be problematical. Most plants are quite happy in
a range of soil ph As to nutrients, soils here can
be lacking in calcium or phosphorous, for instance,
and knowing this before you plant will allow you
to incorporate some before you plant.
In most cases, though, I would say that good plant
growth is the only indicator that really matters.
Alie
How
frequently should one fertilize a vegetable garden?
What are the recommended doses? Also, would it be
beneficial to fertilize a little more often?
RA
Quite a bit depends on the fertility of your soil
and the crop you are growing. In general, you don't
want to over-fertilize root crops -- especially
with anything high in
nitrogen -- while something like a tomato likes
a good amount of feeding. Carrots and onions might
do just fine without any additional fertilizer in
a good soil, while you
might still want to give those tomatoes a boost.
Hard to generalize, but I think the best approach
is to watch the growth of your plants and then respond
by feeding where leaf color isn't where it should
be. As plants approach harvest, though, you want
to drop the amount of nitrogen you give them in
relation to the other elements.
Cornus
I
recently moved from a house that I lived in for
30+ years to a condo...never had problems with my
house plants. Since I moved in September, all of
my house plants have started to develop a white
powdery substance on the surface of the soil. Might
you know what's causing this and is it something
that I should be concerned about? I know that other
residents of this complex complain about the water
and I assume there must be something *undesirable*
in it.
RA
Yes
-- either hard water or fertilizer salts or a combination
thereof is the likely cause. Best approach is to
flush the salts in your containers periodically
by watering heavily until the water really goes
completely through the mix.
Alie
Richard,
I heard somewhere that it is better to add compost
to the flower garden in the fall. Can it be added
in the spring and also in the summer? Also, should
the compost be mixed with peat or other medium?
RA
You
can dig in compost any time if it is well aged and
nicely decomposed and your soil isn't too wet to
dig. You don't need to mix in any peat, but doing
so is fine. If you
want to use it as a mulch, though, one reason you
might want to wait a bit in spring is to allow the
soil to warm up. Placing a thick mulch on a cold
soil in early spring
will delay its warming.
