Category — Containers

Bottom-watering is one of the best tricks I know for saving water in container gardens. But you can make containers even more water-efficient by working from the top down with that old water-saving standby, mulch. Like bottom-watering, mulch keeps moisture levels in the soil more even, protecting plants from the shocks they get when water supplies fluctuate.

And here’s the bonus: mulch will keep your weeding chores to a minimum, too.

The broadest definition of mulch is something that provides a barrier between the soil and air, so moisture stays in longer. That means pebbles can be a mulch. So can cardboard. So can plastic. Some commercial self-watering containers come with a plastic cover that acts as a mulch for the container.

You can also mulch containers in more traditional ways - you just have to think tinier. Instead of big wood chips, use shavings. Instead of hay, use grass clippings, or alfalfa meal, if you’ve got roses or other more nitrogen-hungry potted plants. The woods mulches my plants for free with oak leaves and pine needles; I only brush these away if they’re getting in the way of plant growth. Otherwise, those leaves and needles are providing nutrients and moisture-protection for my plants. (The photo at the top of the page shows some of this natural leaf mulch.)

I’ll confess that I mostly use the most traditional mulch of all: tight planting. If you plant your containers like little landscapes, with groundcovers, tall plants, and seasonal appearances, you’ll find that the plants themselves cover the ground thoroughly.

Before you get to the point of self-mulching plants, you’ll still want to mulch for maximum water savings. The easiest time to mulch is when you’ve just finished planting, when there’s the most visible space between the plants where you can stuff as much mulch as possible. And do stuff. Mulch isn’t effective unless it’s at least two or three inches deep, packed down. That means it has to be even higher and fluffier than that going on.

Of course, that may be difficult to achieve in the confines of a container. Don’t worry about it; if you’ve already got your bottom-watering system going, you’re miles ahead of other container gardeners. Just put on as much mulch as you can, and, when there’s a chance, slip in a little more. If you have tender plants, you can lay on  a complete new coat of rottable mulch at the end of the season; some of it will rot and enrich your soil before you plant again, the rest of it will act as a packed-down mulch base for next season.

Less-traditional mulches, such as plastic and rocks, are a little trickier. Rocks obviously need to go on after planting, but plastic goes on after you’ve got soil prepared and before plants go in. Then you cut an X in the plastic, and slip the plant in (you can also plant seeds this way, but I usually start mine in a seed plug flat before I put them in the bigger containers).

If you live in a hot climate, be careful about the color of plastic mulch you use. Dark plastics heat soils, which is why some people use them, but if you have very hot summers they may heat the soils enough to kill plants, especially in a  small container. Look into more reflective plastic mulches, or consider using traditional mulches that rot. While rotting mulches need to be replaced, they also act as part of your fertilizing system. Plastic mulches need replacement, too - good ones last about two years, in my experience - and they tend to shred and chip and leave little bits of plastic about if you don’t catch them in time.

The same principle applies to rocks: dark rocks attract heat, white rocks reflect it. While rocks allow a bit more moisture to escape, that’s still a consideration when you’re mulching with them. One of the prettiest (and nicely reflective) mulches of this type that I’ve seen is Conscious Gardener’s recycled glass mulch.

Whichever kind of mulch you use, take a look at the top of your container, and think of the best way you can keep moisture from escaping.

Bonus idea: Another way to conserve water from the top is to use foliar sprays made to conserve moisture (they’re sometimes used to provide “shine” for tropical houseplants). The sprays coat the leaves, slowing transpiration (plant breathing, in which moisture is “exhaled”). The coating also makes the leaves slightly shiny, reflecting the sun. I have used these sprays and I think they made a difference, but I wasn’t very scientific about how I used them. I think basically my system works so well without it that I don’t bother, but it might be helpful in some cases.

Next post: putting it all together for a beautiful container garden

JUNE: A MONTH TO HONOR WATER

In a way, my whole blog is about low-water gardening; that’s the reason I got involved with tulips, and I already loved natives and Mediterranean herbs. During June, my posts will all be about conserving water in the garden. This gives me scope to cover everything from containers to cityscapes, soil to site to sprays, and of course portraits of more of those stellar plants that spread their glories with little or no watering. (Hint: the “Wild Plants” category will give you quite a few more; so will the “Bulbs” category.)

Forget the movie. This is the secret.

For some reason, discussions of soil type are often missing from water conservation discussions. That’s a pity, because it really makes a difference.

I started out by trying to grow in containers that were filled with my local clay soil. When I got nothing but wizened and dying plants, I realized that didn’t work. So over the years, I’ve evolved a dirt system that does; I use it, with variations, for pretty much all the containers that I water year-round.

Basic soil: I don’t recommend just dumping some dirt into a container. I do use small amounts of local soil in the containers I plant: this adds some local mycorrhizae, minerals, and other things that plants like (mycorrhizae are kind of like yogurt culture; a little will spread. If you want to know more about mycorrhizae, click the link).

The rest of the soil is your basic potting soil. If I’m feeling lazy and rich, I buy the kinds that have amendments already added. If I’m feeling thrifty and self-sufficient, I get the basic kind and add amendments. The important thing to remember is that soil with lots of humus holds water. Soil with clay holds water, too, but it has no air in it and will turn into an impenetrable block if it dries. Sandy soil will let water run through before plant roots get a chance to drink it. A dose of compost helps everything; it’s a kind of soil-builder and amendment in one.

The usual amendments: Because commercial potting soils tend to lack minerals, I add a handful of azomite (a kind of super-rich-in-minerals rock dust from ancient sea beds) to each large container. Lately, I’ve become enamored of calcium, so now I throw in a small handful of dolomite or oyster shell lime. Acid-loving plants need either a commerical amendment or lots of used tea-leaves. (That’s black tea; others aren’t usually acidic enough.)

In containers where I’m growing plants for flowers and fruit, I put in fertilizers that encourage bloom, usually a pre-mixed organic fertilizer with mycorrhizae, which definitely up the fluffy lushness of my container plants. I sometimes vary these fertilizers depending on what I’m planting, but honestly I often just wind up using the same phosphorus-intensive fertilizer for everything. (Phosphorus is the middle number on fertilizers, and it makes roots and fruit - which also means flowers.)  For heavy feeders, like roses, foxgloves, and lilies, I may add some extra nitrogen fertilizer, such as alfalfa meal, but a lot of my plants get their nitrogen from the humus and foliar feeds alone.

The unusual amendments:  Besides the more-or-less ordinary amendments, I also add earthworms to every pot I own. Earthworms are little fertilizer-factories, taking minerals in and excreting them in a rich, nutritious form the plants can take up easily. They also aerate the soil - important in containers, where dirt tends to pack down hard. I rarely transplant my large containers, and I think the reason is that by adding some fresh soil on top every year, and keeping earthworms in it, the soil gets refreshed without the work of a big upheaval.

The big water-saving secret: The final soil secret is water-conserving polymers, such as TerraSorb. These come in the form of little crystals; you can hardly believe you paid so much for a tub of them, until you try the experiment: put a tablespoon of the crystals in a big mixing bowl and pour on the recommended amount of water. Then watch them swell and fill the bowl.  (The picture at the top of the post shows them lying on a plate.)

This is what the crystals do when they’re mixed in with your soil, gradually releasing water they’ve saved up. You mix them in the soil dry;  when you water, they swell up. It’s sort of an interior version of bottom-watering, keeping soil moisture levels even, and it’s especially good for water-hungry plants. I tend not to use the crystals for plants that like good drainage. On the other hand, if I have plants that like their feet in water, I create a layer entirely made of the crystals on the bottom, and then cover it with crystal-enriched soil.

Eventually the crystals disintegrate into a potassium-based substance that acts as a fertilizer. You can renew them by injecting them into the soil with something resembling a caulk gun (a pro gardener told me about this; I haven’t seen them. But you might be able to improv with a caulk gun). Or you can just dabble little holes with your hands and sprinkle more on top when you renew the soil; that’s the method I use.

Another version of this is mats, made of essentially the same material, that you put on the bottom of smaller pots and planters. I tried this in a seed flat once, but wasn’t as successful as I’d imagined.

Important point: This last water-saving secret won’t work unless you have the good, humusy soil. So all of you who thought you’d make a shortcut and just get the crystals: it won’t work. Sorry. The plants need the whole package.

Next post: keep water from evaporating with mulch - and a bonus idea.

JUNE: A MONTH TO HONOR WATER

In a way, my whole blog is about low-water gardening; that’s the reason I got involved with tulips, and I already loved natives and Mediterranean herbs. During June, my posts will all be about conserving water in the garden. This gives me scope to cover everything from containers to cityscapes, soil to site to sprays, and of course portraits of more of those stellar plants that spread their glories with little or no watering. (Hint: the “Wild Plants” category will give you quite a few more; so will the “Bulbs” category.)

Water-saving containers? I can hear some of you thinking. Are you kidding? Containers dry up quicker than anything.

Well, it’s true. Some of them do. But if you get, or make, the right kinds, your containers can save you water and also save your plants from that phenomenon some container gardeners know very well: death from neglect.

By choosing bottom-watered containers made out of the right materials, I water my container plants twice a week in the really blistering-hot spells; most of the summer, I water once a week.

Bottom watering. Plants actually love bottom-watering. It gives them a steady supply, without the stresses and strains they go through when water dries up, then they get it again, then it dries up…and so on. A consistent supply of water seems to make them very happy, and that’s not just my observation. Self-watering container promos are full of testimonials: “How I grew 50 pounds of tomatoes in one box!”

You can bottom water by using self-watering containers with built-in tanks, like the one in the photo at the top of this post. (The hole is where the hose goes in.) You can also make a self-watering container by inserting a tank into an ordinary plant pot, or by putting that ordinary plant pot into a bulb bowl.

Containers with built-in tanks. These are expensive, but they last for years (none of mine have worn out yet, and I’ve had some for about a decade) and save you water. I have gotten good ones through Gardener’s Supply and Park’s Seeds; other catalogues also carry them. Earth Boxes are a tall rectangular version of this;  others are flatter wider rectangles, squares, and more-or-less traditional round pots. Some of the fancier versions have molded designs and bright-colored resin finishes like glazed ceramic. They come in sizes from smallish hanging planters and pots to honking huge porch planters.

Containers with tank inserts. Here you have two options: buy them (I get mine from Gardener’s Supply) or make them yourself. The basic principle is that there needs to be an insert that keeps the roots out of the tank, but allows the water to wick up into the soil. Here’s a video on making your own self-watering containers from videojug.  If you don’t have high-speed, or you’d like to look at another variant of this, try this site for a writing-and-photos version. The homemade versions may not be glamorous, but you can’t beat the price. And you can do what I do with my cheap pots: hide them behind the nicer ones.

A watering tube poking out of a pot with a reservoir insert

Containers in bulb bowls. Of course you don’t have to use bulb bowls; you can use basins or old turkey roasters or plastic buckets or whatever you have handy that strikes your fancy. But bulb bowls are cheap, and they look presentable. I mean plastic bulb bowls, of course; terra cotta ones suck up water way too fast. I leave the plugs in, so they hold water, set the pot in the bowl, and voila, instant reservoir. If you live in country that’s mosquito-prone, you may not want to provide so many lovely brooding areas for the whiny flyers. But in my dry-summer climate, this is a workable, cheap approach to bottom-watering.

Ollas. While filling in the research for this post, I ran across an article about an ancient method of bottom-watering, used in meso-America. Porous ollas (terra cotta water holders) are buried in the ground with only a fill-hole showing. When filled, they gradually seep water into the ground. Apparently, you can use smaller ollas in big containers, though I haven’t tried this yet myself. This site shows a clever, inexpensive modern adaptation of the ancient olla method that even allows you to “automate” watering (no electricity or running water needed).

Using the right materials.  I’m a big fan of terra cotta - aesthetically speaking. But for those of us who live in dry climates, and for anyone who wants to conserve water, terra cotta is a bad choice. It acts as a wick, sending moisture from the soil the outside air (the same principle that makes it such a good watering tool when it’s buried, as the ollas are). It’s easy to kill a plant in a terra cotta pot in a single extra-hot day. So I use mostly nonporous pots made out of resin and plastic; I have a couple of glazed ceramic pots, too, but they are pretty pricey and very heavy so mostly I stick to synthetics. They’re making synthetics less awful-looking these days, and the plants cover most of them up.  I do have a few terra cotta pots that I use for plants that like a true xeriscape, and I hide some of my less glamorous ones with them.

I do have ecological concerns about plastic, but when I put that against the gas cost of shipping heavy terra cotta, and the fact that the heavy-duty resins last for over a decade (and counting), it seems to me that the artificial materials still come up as the best choice, unless you have local people who turn out large pots. If you make homemade self-watering containers, consider using some type of heavy-duty container as your base. Thinner plastics may start out cheaper, but after a few years they start chipping apart, especially if you leave them in sun. This is the voice of experience speaking.

Next post: Water-conserving potting soils

JUNE: A MONTH TO HONOR WATER

In a way, my whole blog is about low-water gardening; that’s the reason I got involved with tulips, and I already loved natives and Mediterranean herbs. During June, my posts will all be about conserving water in the garden. This gives me scope to cover everything from containers to cityscapes, soil to site to sprays, and of course portraits of more of those stellar plants that spread their glories with little or no watering. (Hint: the “Wild Plants” category will give you quite a few more; so will the “Bulbs” category.)

What if I told you about an easy-care groundcover that integrates plants beautifully in containers and in the ground in early spring, then dies off to leave space for warm-weather annuals? What it I also added that it’s a plant long treasured by herbalists for its nutritious, healing qualities?

Then what if I told you it was chickweed?

Familiarity breeds contempt, and this European plant from the pink family has made itself at home worldwide, in every kind of climate. I have never planted chickweed, and I have never needed to. Chickweed can produce five generations in a season, and its tiny little star-flowers make lots of seeds.

To some, this means it is simply an invasive pest, to be rooted out. To me, it just goes to prove that maxim, “a weed is a plant that’s in the wrong place.”  While others place it squarely in the pest department (any garden-book writeups seem to talk only about getting rid of it), chickweed is always welcome in my garden. It’s pretty, it doesn’t take over, and it gives me a healing spring treat when I pull it out,. And it’s really easy to pull: about three seconds to clear an area of a few square feet.

This means that chickweed also fits well into the low-water garden: instead of replacing it with hot-weather annuals that you have to water, use it as a groundcover for spring bulbs, then leave chickweed and bulbs unwatered for the summer, the way they like it, for an easy-care seasonal show.

The groundcover technique works in pots, too. Chickweed ties things together and makes sense of the jumble of bulbs in this pot, making it into a tiny landscape. I often have such pots, consisting of small bulbs and offsets that need to grow to flowering size. (I don’t throw bulbs away. I figure if they can reproduce in nature, and in the fields of bulb propagators, I should be able to figure out a way to get them to do it here. Sometimes that actually works. But I always live in hope, so I have a lot of pots of random small bulbs.) Without the chickweed, these pots are no works of art; they just have a tangle of assorted foliage from whatever bulbs I stuck in there.

Even with a container monocrop, chickweed is (as its name might imply) stellar. Notice how the little white asterisks of chickweed blooms complement and echo this pot of ‘L’Innocence’ hyacinth.

Chickweed itself is worth some aesthetic appreciation. Euell Gibbons describes it in detail in Stalking the Healthful Herbs: “You will see a single line of tiny hairs running up one side of the stem. When this line reaches the leaves, it continues up the opposites side of the stem to the next pair, alternating the side of the stem on which it chooses to travel at each pair of leaves. ”

And while I’d noticed the tiny star-like flowers closing at night, and on rainy days, I hadn’t noticed what Gibbons saw at the close of evening: “…the paired leaves approach one another so their upper surfaces fold over the tender, developing butds in their axils, and the outermost pair of fully developed leaves envelop the terminal bud as though trying to protect the tender, growing shoot. ”

But chickweed is more than just beautiful in my eyes. Gibbons points out the nutritious qualities; he cooks it in with other vegetables, and uses it in what he calls a Green Drink, a blendered health drink involving mostly herbs. Many people in my area make this kind of drink, but most of the time I prefer using my herbs in tastier ways. Chickweed isn’t particularly delicious, but it’s not bad, either; sort of bland and juicy and crunchy. Sometimes I make it into a tea with other garden foliage (fresh leaves must be simmered gently, covered, for ten minutes to extract the goodies). Sometimes I throw it in salad (I particularly like it in potato salads, but it doesn’t keep well, so it’s best to use it as a garnish at the last minute.) Sometimes I eat the crunchy stems and leaves just as they are, from the garden.

That’s the way chickens like to eat it, so much, apparently, that they gave this plant its most common common name. Other common names are: Mouse-ear, Satinflower, Starweed, Tongue Grass, White Bird’s-eye, Winterweed.

Winterweed, of course, means that it’s a plant which can be used year-round in many areas. Herbalists took advantage of its high vitamin C content; it’s another scurvy-preventing herb, like miner’s lettuce and strawberry leaves. It also has cooling qualities that may be useful in fevers or as poultices on inflammations and itches. (It’s also very juicy, which makes it easy to use as an emergency poultice for a bug bite or sore. Just mash it between your fingers, or between two rocks, and put it on the affected place.)

Herbalist David Hoffman says that this kind of poultice can even help eczema and psoriasis, while Gibbons points out that the old herbalist’s advice to wash wounds or sores in cool chickweed tea might mean that chickweed has antibiotic qualities.

Some herbalists credit chickweed with additional healing abilities; they use it for colds, coughs, tumors, hemorrhoids, sore eyes, and rheumatism. Others claim it’s useless. My best guess is that many of the benefits of chickweeed have to do with high mineral and vitamin content. Cutting-edge nutritional science is finding out something herbalists have known for centuries: a significant amount of illness stems from vitamin or mineral deficiency, or at least is complicated by it.  But not everyone responds the same way to the same treatment; people’s chemistry differs wildly.  Chickweed may well work for some and not for others.

To me, chickweed is beautiful, nutritious, and the ultimate in easy care. Scoff if you will; it will remain one of the quiet mainstays of my garden.

References:

Magic and Medicine of Plants,  Reader’s Digest Association, 1986

Stalking the Healthful Herbs, Euell Gibbons, David MacKay Co. , Inc, 1966

The Herbal Handbook, David Hoffman, Healing Arts Press, 1988

In my case, that title should read, Never For Strawberries. For growing strawberries in strawberry pots in my area poses several problems.

First of all, in our hot, dry, rainless summers, any fair-sized terracotta pot can dry out, killing the contents, in the course of a single relentless sunny day. A largish terracotta pot, like a strawberry jar, might take two. Those of us who tend to be distracted by things in life other than gardening learn this the hard way.

The first year I got my strawberry pots, I innocently put strawberries in them. Since I have very few garden spots involving full sun (my second strawberry pot problem), I used alpine strawberries, white alpine strawberries to be precise, which I got from a specialist catalogue at a very special price. They were alpine strawberries with runners (most alpine strawberies don’t have them), which appealed to me: I could propagate more, because at this price, I wasn’t going to be able to afford to buy them.

The first year I put strawberries in the strawberry pot, the plants in the bottom of the pot went dead after a few weeks. I realized this was because watering from the top meant that the water either evaporated or ran out the side holes before it got to the bottom.

I regrouped. I set up my simplest bottom-watering system, which is to put the pot in a plastic bulb bowl - with the plug still in the hole, so the bowl holds water. This way , the plant has a reservoir of water to draw on, and, in the case of terracotta, the pot itself wicks up some of the water, so it’s a little less porous (read: liable to dry out the soil).

This time, the bottom plants did well, and the top ones died. Same problem, only in reverse. I did try watering from the top and using the bottom-watering system as well, but this was tiresome, and I never did get any strawberries.

I planted the strawberries somewhere else, and retired the strawberry pot. A year or two later, I was overwhelmed with my usual fall influx of spring bulbs. I thought: I’ll just use this strawberry pot as a bulb pot. After all, I don’t water them; they like to be dry in summer. And the terracotta will ensure they get drainage.

So in went my antique maroon-dark Philippe do Comines tulips at the top; in the side pockets went tiny, early-blooming Iris danfordiae.

And for a few years, all was sort of well. The I. danfordiae bloomed the first year, but needed replacing in each coming year, so while they accepted the strawberry pot, they weren’t exactly happy there.

The Philippe de Comines bloomed for a couple of years, then went blind. (On reviewing this post, it came to me that I should explain this. My tulips did not look at an eclipse or a Day of the Triffids meteor shower and suddenly become unable to see: what happened was that they continued to put up single spears of leaves, but didn’t bloom. That’s how bulbs go blind.) When I finally dug them up, they had split into many tiny bulbs, ready to be grown in a bigger space, so they could mature and bloom. They had always looked a little short for the tall strawberry pot, anyway.

I transplanted Philippe de Comines into other containers. That left the strawberry jar empty. Where it sat until recently, when I was in dire need of transplanting one of my lavenders.

Looking around for pots - if there were a portrait of me as a gardener, it would be me looking around for pots, preferably in a noble pose, like stout Cortez and his companions, viewing the ocean and each other with wild surmise* - looking around for pots, I spied the strawberry pot. Empty.

I had to peel back the root layers from my lavender; it really had gotten awfully  potbound, and the pot it was in was wider than the strawberry pot. But much shallower, I reasoned to myself (or perhaps to the lavender). The strawberry pot would give the lavender more root room, and after the radical cutting back I’d given it on top, I expected great things. Since it’s one of the more compact lavenders (knee-high ‘Rosea’, with pink flowers - really mauve in my climate and soil), the proportions should be right for the strawberry pot when it grows out. At least that’s the vision.

But what about the side pockets? While cleaning up in another large container, I was inspired: here was one of the places I’d dumped my little bearded iris roots. Since I hadn’t had a place for them last fall, I just slipped them into any container that had a spare slice of room. They weren’t doing very well, because they didn’t have much sun in those crowded conditions. They were alive, though, which had been the point of the exercise.

Now I thought: what about putting them in the side pockets of that strawberry jar? Bearded iris don’t like being buried deep; they actually prefer to be partly out of the soil, so they’ll be all right in there (soil tends to settle and sift from the pockets, leaving the roots of whatever’s in them exposed). Neither one of them has to have water to barely survive, so an occasional summer watering would probably keep them in decent shape. And the combination might look cool in that pot, grey-greens against dark terracotta.

So that’s where I put them. The iris and lavender are waiting: will they be the final epoch of my strawberry pot? Or will it need renewal next year?

Next post: about those alpine strawberries and what happened to them

* leaving out the mass murder bits. For those of my readers who know Cortez only from Keats, his progress through the Americas was marked by the kind of slaughter, torture, and lies that the Nazis (or some previous U.S. governments) could have taken pride in.