Argania and palm seedlings in a bottle (Willem)

Some weeks ago, I got some seedlings of Argania spinosa and a palm tree growing in my garden. I transplanted them in a plastic bottle to study the possibilities to grow them with a minimum of water.

The potting mix in the plastic bottle was treated with 5 g of the soil conditioner TerraCottem per liter of soil. The water stocking polymers of the TerraCottem reduce the irrigation needs by 50 %.

Seemingly the 3 seedlings are doing very well.

Argania seedlings and palm seedling in bottle
Two Argania seedlings and one palm seedling growing together in a plastic bottle. (Click on the photo to enlarge it).

Combating desertification and food insecurity with container gardening (N. ROTH / Willem)

Today, I received an interesting comment of Nancy ROTH on my former posting :

Great ideas for container gardening (Willem) August 14, 2007

I’m having a hard time imagining how this containerized approach, nifty as is appears, could be helpful at the scale needed to reverse desertification or to feed a major population. Isn’t it rather labor-intensive to create a separate container for each plant? Don’t the seedlings rather rapidly outgrow their containers? Then where do you plant them in the desert, which cannot sustain them?

Combating desertification and food insecurity with container gardening

Let us try to link different aspects of container gardening, desertification, desert gardening, food production, education and ecology.

Knowing that millions of plastic bottles and plastic shopping bags are littered every year all over the world, in particular in the desertified areas, it seems indicated to find incentives to get the local people aware these pollution problems.  Learning people, especially children, how these bottles and bags can be used to produce vegetables and young tree, seems to be a valuable (and acceptable) way to motivate the population to take care of the environment.  Less littering means less pollution, a form of desertification.

Motivating children to grow vegetables and young fruit trees in self-watering containers at school contributes directly to solve two major problems : pollution of the environment (less plastic flying around) and malnutrition (daily fresh food at school).  Moreover, the young fruits trees can be taken home at the end of the school year, planted around the house and thus contribute to reforestation (or afforestation) and provision of healthy fruits, not to forget the fact that the plastic bottles or bags should be buried at plantation time.

Considering desert gardening : it is quite difficult to improve the soil qualities in the desert, in particular its water holding and nutrients retaining capacities (too much leaching).  Let us imagine that in  small family garden a series of self-watering containers, e.g. plastic bottles and bags, are buried in the garden soil.  These containers can be filled with “improved soil” (for instance treated with manure).  As more water will be retained in the containers (less infiltration), more biomass can be produced with a smaller quantity of water and less fertilizer (less leaching).  This higher water use efficiency leads to higher food production and less influence of drought on crops (more food security).

Around the gardens, living hedges can also be grown in containers buried in the soil.  There is a significant enhancement in survival rate of the shrubs and trees in the hedges an those plants are growing quicker with less water.

From the educational point of view, container gardening is a fantastic tool for the teachers at school.  Less difficulties for the pupils to keep the school garden in good shape, closer contact with the growing plants in or around the classroom, opportunities to teach the kids a lot of things about differences in plant development from seed to vegetable or tree, are but a few benefits of this container gardening method.

You are most certainly right that it is hard  “imagining how this containerized approach, nifty as is appears, could be helpful at the scale needed to reverse desertification or to feed a major population”.

We are not claiming that container gardening itself can reverse desertification or feed  major population.  However, should every family apply container gardening, should every child at school take care of its own containers, it would create a new attitude, more awareness, less fatalism and neglect, more hope for a better future.

Of course, one needs a lot of support to introduce these ideas.  It will take a lot of time to convince people.  But the fact is quite clear : where container gardening is accepted people eat more fresh food and the environment is gradually cleaner.

It’s a simple as putting our shoes on !


Mahonia seedlings in selfwatering containers (Willem)

The mahogany shrub (Mahonia aquifolium) in my garden has been flowering and fruiting.  Its dark blue berries are normally eaten by the blackbirds, but this year I collected them in time, kept them drying for a couple of weeks and then planted the dry berries in a tray.  Other berries were opened and their little 2-3 kernel were taken out and washed.

Last week some of the berries in the tray germinated (the kernels did not yet).  I have planted some mahogany seedlings in a small coca-cola bottle, transformed into a self-watering container (see my photo below).  I expect that these seedlings will grow well, so that I can take the young trees to S.W. Algeria, where I want to introduce them as thorny shrubs to form a strong living hedge around the small family gardens in the refugee camps.

Mahonia seedlings in selfwatering container
(Click on the photo to enlarge it)

My self-watering containers with the mahogany seedlings :

(1) In front, a leaf of my mahogany shrub.

(2) Two yoghurt pots in which I can easily pour some water (serving as a mini water reservoir or tank).

(3) In each pot, an inverted coca-cola bottle of which I cut the bottom, filled with potting mix and TerraCottem soil conditioner, with a mahogany seedling planted on top.

(4) I left the lid (stop) on the bottles, but perforated the neck, close to the lid, at two opposite sites.

(5) The bottles are sucking up water from the yoghurt pots through the holes in the bottleneck.

(6) Water is stocked in the TerraCottem soil conditioner.

(7) Mahogany roots are growing towards the gel lumps of the swollen polymers.

(8) With a minimum of water and fertilizer the seedlings will be growing into nice young trees.

(9) The bottles will be cut vertically in two halves and buried in the plant hole at the moment of tree plantation (avoiding pollution of the environment with plastic).

Tree seedlings in a plastic bottle (Betula alba)

Since some months, I am experimenting growth of tree seedlings in transparent plastic (PET) bottles.  It’s a real success for a number of reasons:

(1) The potting mix, to which I have added a very small amount of water stocking soil conditioner TerraCottem (5 g per liter of soil), is kept continuously moistened (less evaporation, less heating effect than in the classical black plastic grow bags, used in nurseries)

(2) Individual watering of the bottles has a beneficial effect on plant growth.

(3) I can keep my seedlings in daily sight by having the bottles on the terrace.

(4) When the young trees are tall enough for plantation on site, I will dig a plant hole, cut the bottle vertically in two halves, tear the two halves apart and leave them on the bottom of the plant hole when filling the pit with local soil (to which I will add again some TerraCottem).

(5) This way I will take care of the environment by reusing the plastic bottles and finally burying them.

Here are a couple of photos of a young birch tree (Betula alba) growing in a plastic bottle :

Young birch tree in bottle   Birch tree and succulent in bottle

Young birch tree (Betula alba) and a succulent plant growing together in a plastic bottle. (Click on the photos to enlarge them).

Raised beds combined with containers for inside gardening (Willem)

Today, I received an interesting comment from Anne WALKER on my former posting :

Different aspects of rooftop gardening (Google Alert / Salt Lake Tribune) July 13, 2007

If a garden can be grown on a roof top, how about on the parking lot of an old abandoned strip mall. It is late in the season to start a garden, but we just received funding. We also have donated space in a building located in a strip mall. There is a fenced in area that I’d like to create a few raised beds and perhaps apply lasagne gardening in the beds. What do we do about drainage? How do we keep the soil and water from running out under the beds. Do we line with plastic? Help!!! This is a late summer youth project, funded in part from Community Block Grant and State arts funds.”

Here is my reply to her :

Dear Anne,

Thanks for contacting me and congratulations for your nice ideas.

Raised bed gardening offers a lot of opportunities to embellish our environment or to grow plants in any “difficult” place.

Let us first consider the outside parking lot (or is it inside ?). I see no problem to install raised beds there. Would a bit of water running out be a problem ? Then, I recommend to make the beds a bit higher (1-2 feet), to line the bottom up with a strong plastic sheet forming a shallow reservoir, to fill the bottom part of that reservoir (2-4 inches) with granules of expanded clay (also used in hydroponics) and to cover these granules with a good potting mix to which I would add some water stocking polymers or, even better, a soil conditioner like TerraCottem (see <;).

About the raised beds inside the building : see above, as I cannot foresee any problems with water.

Let me now make another suggestion !

Why don’t you construct a raised bed and fill it up with containers (each of them perforated at its bottom for drainage). I am thinking at the classical plastic flower pots, but also at PET bottles or even big plastic party cups (use your imagination).

The raised bed should be constructed like the one described above : with plastic lining at the bottom, but without clay granules. The containers (pots, bottles or cups) can be put directly on the plastic sheet (in the so-called reservoir) and filled with a good potting mix (mixed with water stocking soil conditioner), then seeded or planted. Now all the containers are covered (mulched) with a thin layer of potting mix, so that one cannot see the containers anymore (only a nice layer of soil under which the containers are hidden). When watering such a raised bed, most of the water will be running into the containers and stocked in the polymers. A surplus of water, running through the containers or through the open spaces between the containers, will run into the plastic sheet reservoir and only a minimum will be kept for a short time on that plastic sheet (from where it will be gradually absorbed by the potting mix in the perforated containers).

I can imagine that after a while one would have to add a thin supplementary mulching layer of potting soil, for the soil will slide partly down into the open spaces between the individual containers.

I never did this before, but I can imagine that this would be quite successful. Worth trying, I think !

Please keep me informed and possibly send me some photos of your realization. I will gladly publish them on my blog.


Containers are thirsty : here is a solution (Vegetable Grower / Willem)

Read at :

The Vegetable Grower

Containers are Thirsty

Even though I have a number of raised beds I still like to grow veg in containers. Why? Because there is always some little area somewhere in the garden that I can slip a container or two into and capitalise on the `wasted` space. But this time of year be careful to check on your containers often as they can dry out very, very quickly – those plants are very thirsty in sunny weather.  It may be that you need to water a couple of times a day in hot weather. I had a largish container with four climbing French Beans in last year and boy were they thirsty and watering twice a day was the norm in hot weather – they have masses of fine rots which filled the container in no time. If you see the compost shrinking away from the sides then it is becoming too dry and you may need to soak the container in a bucket (or some such water holding container) for a couple of hours to re-soak the drying compost. If it is too dry it becomes `waterproof` and any water being poured on will mostly run down the gap between the compost and container side. 



Containers drying quickly is one of the common problems for container gardeners. I am happy to tell you that I have excellent results when mixing the potting soil with a soil conditioner like TerraCottem (see  It is mixture of some 20 different substances, on the basis of water absorbing polymers.

We all know the problems with dried “organic” potting soil or compost, becoming even waterproof.  Well, I am using all kinds of containers, preferably PET bottles and plastic shopping bags (as grow bags).  I am filling them with a classical “universal” potting soil, containing a lot of organic matter, to which I add 5 g of TerraCottem per liter of soil.  At the start, I am watering to saturation, in order to get the water stocking polymers swollen to  maximum.

There is less evaporation in the bottles and bags.  The rootlets are sticking themselves to the swollen hydrogels and are even penetrating them (all kinds of nutrients are also absorbed by these gels).  The potting soil is shrinking less.  Of course, there is always the transpiration of the plants, so that I have to water from time to time, but certainly not every day, even in the hottest periods.

Let me recommend container gardeners to give it a try.  And even if you don’t have the TerraCottem soil conditioner in your area, set up an experiment with water stocking polymers to be mixed with your potting soil.  Success !

A special container form : the grow tower (Willem)

Years ago, I visited a colleague in Beijing (Prof. Dr. WANG Tao), who showed me a peculiar way of growing garlic plants on vertical “poles”. In fact, the poles were PVC pipes, about 10-12 cm (4-5 inches) in diameter, in which a series of 4-5 cm (1 ½ to 2 inches) holes were drilled. The holes were spaced randomly around the pipe, about 4-5 cm (1 ½ to 2 inches) apart.

An impressive series of pipes were standing as “grow towers” in a greenhouse, so that in a relatively small space a maximum of plants were kept growing from floor to ceiling. Each pipe was filled with potting soil and the pipes were watered with a sort of drip irrigation system. In every hole of each grow tower a garlic bulb was growing splendidly (flowering towers !).

This brought me to the idea that a smaller number of plants could also be grown on PET bottles. It suffices to cut a number of holes in the wall of the bottle, filled with potting soil, to create a small grow tower (see my first experimental designs) :

Vertical grow tower

Bottle with 3 holes at one side. The same number can be cut at the opposite side. (Click on the picture to enlarge it).

Bottle grow tower

Mini grow tower : holes cut in the bottle wall fashioned with scotch tape.


I intend to set up some experiments with similar grow towers next week and I will post the results as soon as possible.


Today, I was reading an interesting description of other types of grow tower, made in wood. Here is the text that I found in The Tucson Gardener (2004) :

The Homemade Strawberry Tower
ou would think by now that I’d be out of new strawberry plants but I wasn’t. I still had about 50 young, healthy plants that needed to find a place in the garden or were destined for the compost bin. I happened to read where someone suggested drilling holes in a whiskey barrel filling the barrel with potting soil and the holes with strawberry plants. That’s when I decided I’d build a grow tower from inexpensive wood just to see what would happen.

Using cedar fence boards and lots of screws I made a four foot tall by about 15 – inch square container. Then I drilled a bunch of evenly spaced inch and a half diameter holes.

I then treated the outside of the wood with a water sealer and moved the whole thing to a place in the vegetable garden where I placed it on four concrete stepping stones to keep it from sitting on the ground. I ran a loop of soaker hose down to the bottom of the four foot tower and hooked it up to the watering system.

Then came the hard part – planting the strawberry plants. I filled the container with a good potting mix and some slow release fertilizer putting plants in the holes as I filled the tower. At the top I added a few more plants. Eventually I had to replace three plants that didn’t make it because I may have planted them too deeply covering the crown.

I had plans to make a removable cage that I could slip over the tower with the beginning of fruit production to fend of birds and rodents but production wasn’t so great that I needed to build the cage. I did construct a simple frame to support shade cloth to help the plants make it through the hot summer.

I must admit I like the looks of my tower but it hasn’t been a big strawberry producer. My biggest fear is it may fall apart sooner than I’d like. I’m hoping it will last for three years. The verdict isn’t yet in. Until then the strawberry tower makes and interesting addition to the vegetable garden.(2004)”


Looking at all these possibilities to construct “grow towers” from pipes, bottles, barrels, wood etc., I am wondering if some of you would come up with more interesting ideas. I am looking forward to your descriptions and preferably with photos.

What a wonderful world, this container gardening, in particular for people living in the drylands, who can grow vegetables and fruits without needing to install gardens in desertlike soils, saving a lot of water and getting fresh food with minimal efforts !


My very simple strawberry bottles (Willem)

Having read Marie IANNOTTI’s excellent article on “How to plant a Strawberry Pot (Strawberries Optional)“, I want to show the good results that I obtained with strawberries growing in my plastic bottles :


Using classical PET bottles, I first perforated the bottom (making two tiny little holes of 2-3 mm).  Then, I have cut the upper cone of the bottle, made a slit in the wall of it (to be able to fold the cone a bit) and pushed it in the bottle, down to the bottom to form a sort of a dome over the drainage holes (stop taken off).

After filling the bottle with potting soil (mixed with a bit of water stocking TerraCottem soil conditioner), I planted a young strawberry plant on top, compacting quite well the potting soil by pushing it down, leaving a cavity of some 5 cm (2 inches) at the top of the bottle (for ulterior watering).

As a maximum of irrigation water is kept in the bottle (surplus is drained) and there is less evaporation, the potting soil with the TerraCottem keeps the inside of the botttle moistened for a longer time.  Thereby, the strawberries (or other plant species, even young trees !) are growing continuously almost without any water stress.

It’s simple and very cheap, but the results are remarkable (see  the picture above).  I am sure that the same results can be obtained with very cheap plastic shopping bags, that can easily be transformed into “grow bags“.

Soil amendments (Google Alert / Salt Lake Tribune)

Read at :

Google Alert for gardening

Salt Lake Tribune

Gardening: Soil amendments that pull their weight


By Maggie Wolf
Special to The Tribune

* MAGGIE WOLF is an assistant professor for Utah State University Extension in Salt Lake County. E-mail her at


Nothing beats homegrown compost


The true secret to a great garden is as plain as the dirt under your nails. Healthy soil begets healthy plants. But how can you transform ancient lakebed into sweet-smelling, brown, crumbly soil? Mixing in soil amendments create a shortcut around the long road to organically rich soil, but amendment has strengths and weaknesses. Choose the route that best suits your soil, site, time and budget. Here’s a brief rundown: Continue reading Soil amendments (Google Alert / Salt Lake Tribune)

Different ways to use plastic bottles for gardening (Willem)

There are numerous ways to use plastic bottles for growing plants with a maximum of water use efficiency.  Here are some of them.

1. Bottle top covering the bottom

Bottle top at the bottom
(Click on the picture to enlarge it)

a. Perforate the bottom to create a drainage hole (2-3 mm wide is sufficient).

b. Cut the top (cone), make one slit in the lower edge of it, and slide it into the bottle so that it covers the drainage hole.

c. Fill the bottle with potting soil (possibly mixed with a water stocking soil conditioner like TerraCottem, see

d. Leave 5 cm (2 inches) from the top to form a cavity for irrigation.

e. Seed or plant a seedling.

Papaya seedlings
Papaya seedlings in bottles with top cone as an air chamber over the perforated bottom.

2. Bottom part of a bottle as a reservoir and a wick

Use a wick

a. Cut a bottle in half and use the bottom part as a water tank (reservoir).

b. Take a second bottle of the same dimensions and cut 2-3 cm (1 inch) of the bottom.

c. Leave the stop on top, but perforate the cone (2-3 mm) to create an opening for the wick.

d. Push the wick through this opening, so that it can hang in the water tank and run through the bottle to hang over the top (see picture above).

e. Fill the bottle with potting soil (possibly with the water stocking soil conditioner TerraCottem).

f. Position the bottle with soil on the water tank with the wick hanging in the water.

g. Seed or plant a seedling.

Bottle with wick and mint
Bottle with wick on a water tank (reservoir). Mint cutting develops well.


Joseph TOLLEDOT told me that he simply had cut a bottle in half, used the bottom half as a water reservoir and the top one as container for plant growth (see his pictures on
3. Perforated top and bottle sitting in a water tank

a. Perforate the cone of a bottle top at two opposite sides (holes 2-3 mm).

Perforated cone
Cone perforated at two opposite sides.  Leave the stop on top.

b. Cut 2-3 cm (1 inch) of the bottom.

c. Fill the bottle with potting soil (possibly mixed with a water stocking soil conditioner like TerraCottem, see

d. Seed or plant a seedling.

e. Position the bottle in a water tank (lower part of a bottle or simply a plastic pot, e.g. a yoghurt pot)

Perforated cone in a water tank
Bottle with perforated cone in a pot (as water tank)

Should you have more interesting ideas to use plastic bottles for gardening, do not hesitate to send them to me (see comments).