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Q."I Canna Change the
Laws O' Physics, Captain!"

I’ve got some very large, tall decorative containers in my design this year, and I don’t want to fill them with huge amounts of potting soil. I’ve heard that you can fill most of a container with bulk materials like packing peanuts or even soda cans to conserve the potting soil.

-A.K. in California, by voice-mail
A.
True enough, A.K., and the same technique of putting non-absorbent filler material at the bottom of a container is often used to promote good drainage as well. Although I don’t recommend it for either use in most containers, in the case of your large, tall containers the soil physics will work to your advantage.

The theory goes that non-absorbent stuff like gravel, oyster shells, broken potshards or those Styrofoam packing peanuts, placed under a shallower layer of potting medium will let excess water run out and prevent the plants’ roots from rotting in a saturation zone of standing water. Intuitively it makes sense.

But physics aint necessarily intuitive! See, the shape of a container and the particle size of the potting medium all determine how water moves. Fine particles hold a lot of water, while coarser particles, which have more space between them, let excess water pass.

The best potting media are a balance between these fine and coarse particles, making a goldilocks mix that’s not too wet, not too dry. But water doesn’t flow well from fine textured media to coarse textured ones, like a non-absorbent filer at the bottom of a pot. It has so much space, that drainage is actually arrested. The saturation zone of the pot is driven up to the layer of potting medium, essentially creating a shallower container.

On the other hand, if you have well-balanced potting medium filling the entire container, gravity will guarantee that the saturation zone will be at the bottom, whether the container is six inches tall or 6 feet tall.

How does this affect your containers? Depending on what plants you’re going to be installing, the depth of their root systems and the amount of water they need, you can adjust the height of your non-porous filler and the depth of your potting medium to make a perfect virtual container inside the big, tall show pieces.

Just use plants with similar requirements. If their root zone is, say, 4 to 6 inches, fill your container with a foot of potting medium on top of the non-porous fillers at the bottom. You’ll have enough soil to sustain the plants with a saturation zone between the filler and the bottom of the soil layer and still not have to fill the rest of the space with pricy soil mix.

Q.Black Arts for Black Spot?
Do you have any secret, homemade brews that will get rid of fungi and other plant diseases?

-S.L. in Nebraska, by e-mail
A.
It seems almost a prerequisite these days to have some kind of arcane, sub-rosa recipes known only to "garden gurus".

I think I’ve heard of many of them, like concoctions of baking soda and soap, mouthwash, hydrogen peroxide, vinegar and even compost tea. Some just don’t work, some do but not for the reasons you’d think.

For getting rid of powdery mildew, the mouthwash formula is one cup of an ethanol-alcohol-based mouthwash in three cups of water applied once a week.

Two to three tablespoons of apple cider vinegar,
5 per cent acetic acid, in a gallon of water once a week is recommended for black spot as well as powdery mildew.

Three per cent food grade hydrogen peroxide has been used weekly both undiluted and at a half strength dilution.

And there’s the widely touted baking soda and soap spray, one tablespoon of baking soda and one or two teaspoons of real soap, not detergent, to a gallon of water.

All of them tend to work ok on powdery mildew, but then so does spraying the plant off once a week with a jet of water. If you don’t mix baking soda with soap it just blows off the plant after it dries, and it really needs to be applied to the plant before any fungal damage is evident.

Hydrogen peroxide’s chemical formula is H2O2; it's very unstable and loses that second O very quickly, becoming oxygen and water. It's great for disinfecting something immediately- it's often used on strawberries to treat them for mold before they’re shipped. But it has no staying power on plants.

Vinegar preparations have a pretty good track record at controlling black spot as well as powdery mildew, as does the mouthwash concoction. Just be very careful of the concentrations of acid or alcohol. You could end up burning your plants.

All in all the data show these natural remedies are marginal on black spot, ok on powdery mildew, but again so is a jet of water once a week. If you have really nasty infections I’d suggest trying something specifically made to go after fungus like Bravo or Daconil- or use an organic fungicide like neem or jojoba oil.

There’s also Bacillus subtilis, a soil bacterium that controls bacterial spot, powdery mildew, rust, gray mold, leaf blights and scab. And remember, the operative word here is control, not eradication. More is not better, organic or not. These may not be the nuclear chemicals used in agribusiness, but they should be used and treated with the same respect and care you’d give the heavy hitters.

Q.Not Craw... "Craw"!
I found a really odd looking growth popping up out of a mulched area of my garden. It was tinged pink to red and orange and sort of deformed looking, like a crab claw. Is this some kind of mushroom and is it dangerous?

-E.B. in Nebraska, by e-mail
A.
You’re describing lobster mushrooms- which aren’t really a kind of mushroom, they’re the result of a parasite on a parasite- a fungus called orange mushroom pimple (Hypomyces lactifluorum) that attacks other mushrooms, causing them to change color and grow into that deformed lobster claw shape.

They usually show up after rains or other humid weather and are the reproductive structures of fungi that are growing in the decaying wood of the mulch. They’re not infective of other plants in your garden, and some folks like to keep them around for the bright colors and unusual shapes.

If I had kids or pets I’d pop them out with a rake for safety sake. Otherwise, once they exhaust their food supply in the mulch, they’ll disappear.

Q.Getting Smaller Every Year
I love starting seeds indoors for my garden each year,
but it’s becoming more difficult every season to see and manipulate those tiny ones. Have some suggestions?
-D.D. in Pennsylvania , by e-mail
A.
Well, D.D., lots of us are starting to find those super tiny seeds, such as poppy, basil or carrot, more of a challenge to work with as the years go by. Fortunately most of those tiny seeds are designed to be broadcast to the soil surface rather than planted at any depth like, say, beans or peas.

I thoroughly mix the tiny seeds in with either super fine silica sand, the kind used in outdoor ashtrays, or unflavored gelatin. Put the mixture in a saltshaker or on of those cheese shakers you can get from restaurant supply houses. The seeds end up well distributed in the easy to see sand or gelatin, so when you shake a nice, even coat over the soil surface, you can be confident of getting uniform application of your tiny seeds.

I also press the stuff firmly into the soil surface to get good contact with the seeds, and if the seeds need light to germinate, such as lettuce, I add a very light layer of vermiculite. This protects them and keeps moisture in the soil. For seeds that need darkness to germinate, such as parsley, I’ll add enough soil mix to completely cover them.

Q.Blowng Hot or Cold?
I’m just getting started with vegetable gardening from seed and don’t quite get some to the terms the old timers throw around, like “warm season crops” and “cool season crops”. What does that mean- the season you plant them in, the season they grow in, or something else entirely.
-G.L., Oregon, by e-mail
A.
“Warm” or “-cool season crop” is a kind of shorthand for the weather and environmental conditions the plant likes to grow in. But that also gives you a lot of information about the right conditions for planting and germination, soil moisture, light, all those things.

For example, cool season lettuce is best planted in early spring or fall, when the air temperature is lower. The soil temperature doesn’t need to be as warm for them to germinate and they don’t need as long a day period as, say, cucumbers, which need both warm soil and air temperature and a long day period with more intense light.

The “season” a plant likes to grow in also give you a hint about which ones can be interplanted for maximum yield in a vegetable garden or to keep color in an ornamental garden bed- some developing quickly in the early season while others take more time and come into their own after the early guys have gone by.

Cool season vegetables include beets potatoes broccoli onions cabbage peas carrots radishes cauliflower spinach collards turnips of course lettuce.

Warm season veggies include beans, peppers, cantaloupe, squash and pumpkins, cucumbers, sweet potatoes, eggplant, sweet corn and tomatoes.

For a really in depth lesson on the seasonality of plants and interplanting, check out Carrots Love Tomatoes: The Secrets of Companion Planting for Successful Gardening by Louise Riotte or Square Foot Gardening by Mel Bartholomew. They each have excellent explanations of the envionmental variables plants need and how to use that to maximum effect in the garden.

Q.Avoid A Fishy Environment
I'm getting ready to landscape a koi pond and waterfall my husband installed last fall and I have a good idea of what I want to plant. But I've listened to you talk about designing the whole ecosystem of a landscape and not just what looks pretty. With that in mind are there any plants I shouldn’t install around this water feature.
S.L., Oklahoma, by e-mail
A.
Thanks for such a good and timely question. Now is the prefect time of year to be thinking about plants for a spring landscaping project.

The leaves, flowers, bark, seeds or roots of these plants can definitely cause some problems and should keep their distance from a water feature with fish:

Azalea (Rhododendron spp.) Black Locust (Robinia spp.) Buttercup (Ranunculus spp.) Caladium (Caladium xaiitliosoma) Castor Bean (Ricinus communis)

Chokeberry/Cherry (Prunus spp.) Climbing Nightshade (Soanum dulcamara) Jack in the Pulpit (Arisaema spp.) Angel’s Trumpet (Datura spp.) Lily-of-the-Valley (Convallaria majalis) Pigweed (Amaranthus spp.) Red Maple (Acer rubrum) Sweet Pea (Lathyrus spp.) Flowering Tobacco (Nicotiana spp.) Tomato (Lycopersicon esculentum) Yew (Taxus spp.) Oleander (Nerium oleander) Oak (Quercus spp.) Russian Olive (Elaegnus angustifolia) Black Locust (Robinia pseudoacacia) Snow on the Mountain (Euporbia spp.) Hellebor (Helleborus niger) Lantana (Lantana camera) Lily of the Valley (Convolaria majalis) Solomon's Seal (Polygonatum spp.) Morning Glory (Ipomoea spp.) Dwarf MorningGlory (Convolvulus spp.) Fritillaria (Fritillaria spp.) Stonecrop (Sedum spp.)

Q.Frozen Fish?
Last winter all the fish in my water garden died. I was told if the pond was deep enough the water wouldn't freeze and the fish would be ok. What happened?
N.M., Minnesota, by e-mail
A.
The ice didn't do your fish in directly, but it was the cause of your losing them. Even in the winter, organic material is decomposing at the bottom of the pond... stuff like leaves and fish waste.

This decomposition generates toxic gasses, and when a water feature freezes over the solid layer of ice traps these gasses and prevents them from leaving the water.

First, try to keep leaves and other organic material out of the pond by putting netting over the surface of the pond. That ½ inch square netting used to keep birds from taking fruit off of fruit trees works well. Large rocks or bricks can hold down the edges of the netting while the leaves are falling.

Then use a skimmer or water-pressure powered vacuum to suck the stuff from the bottom of the pond before you wrap it up for the winter. Then, put an electric pond deicer or live stock water tank heater and float it in the pond. It will keep a small area of the pond's surface ice free and open to let gasses vent and oxygen into the water.

Q.Fuming Over Greenhouse Gas
I have a small hobby greenhouse that I heat over the winter with an unvented propane space heater. I'm concerned that the fumes are hurting my plants. Should I be worried?
M.H., Washington, by voice mail
A.
If you're using the kind of little space heater I'm thinking of, which burns a tiny amount of propane and is designed to be operated unvented in occupied rooms, there won't be any permanent damage to your plants.

The blooms of tropicals might fade and drop a little sooner than normal, but the other plants you're holding in your greenhouse shouldn't be effected.

Just for safety sake I'd get a carbon monoxide detector and install it in the greenhouse so you'll know if any CO is present before you go in.

That' a good idea for key areas of your house, too. I have a CO detector installed right next to each of my smoke alarms.

Q.Chilling Tulips are Blasted
Every year I chill pots full of tulip bulbs in the garage refrigerator, and the flower buds form but don't open. What's happening?
T.S. from Fulton Missouri, by e-mail
A.
Your tulips are experiencing bud blast... They shrivel up before they open.

I'll bet along with the pots full of tulips you're also storing some fruits or vegetables in that fridge. They emit a colorless, odorless gas called ethylene that causes them to ripen and, ultimately, spoil. This ethylene gas also blasts the tulips.

Once the bulbs have been damaged you have to throw them away. Put pots full of fresh bulbs in plastic bags, checking them frequently to make sure they aren't getting moldy.

You might also want to look into some of the ethylene gas absorbent products on the market and put a pouch or two in the fridge. Better yet, because you live in a region of the country that gets nice and cold, chill your tulips in an outdoor cold frame or in an unheated garage, completely away from stored fruits and veggies.

Q.A Case of Mistaken Identity
I've grown Peruvian daffodils in other gardens in the past, but this year they weren't nearly as fragrant as before. What am I doing wrong? very year I chill pots full of tulip bulbs in the garage refrigerator, and the flower buds form but don't open. What's happening?
B.L. from California, by e-mail
A.
Likely nothing. It might just be a case of having planted the wrong bulb.

You probably had Pamuanthe peruviana, which is very fragrant, in your old gardens. This time you could be growing Hymenocallis narcissiflora, which is in the amaryllis family and not nearly as sweet smelling.

Both are called Peruvian daffodils, and both like the same conditions, full sun and moist, well-drained soil. Both have the same dark green, strap-like foliage. But the hymenocallis is also called the spider lily because of the huge 4 inch curled petals that surround the white flower cup.

The Pamianthe has much shorter petals that aren't curled. Check out the photos at right to see what I'm talking about.

I'd recommend getting in contact with some of the specialty growers on line and make sure you're getting the right bulb by ordering it with the latin names.

Q.Black Oil Sunflower Blues?
We feed wild birds black oil sunflower seeds. But I've heard the hulls will ruin our compost. What's the story?
R.H. from Tennessee, by e-mail
A.
Black oil sunflower seeds are terrific for wild birds. They have high energy content and the thin shells are easy for little birds like chickadees, juncos and sparrows, as well as doves, to crack.

But as the hulls decompose in the compost pile they exude a substance that inhibits seeds from sprouting.

You may want to switch to hulless sunflower seeds. They're as easy for the little birds to eat as black oils, and they frankly make less of a mess.

If you'd like to stick with the black oil sunflower seeds, instead of composting them, put a cup of the hulls in 4 cups of water and puree in a blender.

Then pour the slurry into the cracks of the sidewalk, along the fence line and anywhere else you'd like to keep free of weeds. It makes a great preemergent weed blocker