Top blogs on Botany (K. SONORA / Online College Blog)

“We just posted an article, “Top 100 Botany Blogs” ( I thought I’d bring it to your attention in case you think your readers would find it interesting. Kelly Sonora”

Top 100 Botany Blogs | Online College Blog and School Reviews

Students of botany and amateur plant enthusiasts alike can take advantage of the information offered up by these bloggers.

Online College Blog and School Reviews

Plastic bottles and bags: precious jewels for container gardening (Willem)

On September 12th, 2007 Riziki SHEMDOE sent the following message :

“I have been reading on the container gardening experiments that you have been doing. This has encouraged me to put up a proposal on introducing this technology to the rural semiarid areas of Tanzania where normally crop production is very poor due to drought and poor soil fertility. I am requesting to know whether there are some best practices from the third world countries that you have come across regarding the use of this technology in improving rural food security and poverty alleviation? I will be grateful if you share with me some of the best practices so that I may use them to strengthen my proposal. I look forward to reading from you.
Kindest regards,
Riziki. “

Riziki Silas Shemdoe (MSc)
Institute of Human Settlements Studies,
University College of Lands and Architectural Studies
P.O.Box 35124 Dar es Salaam, Tanzania

Here is my reply :

The easiest and most practical way for people in developing countries to practice container gardening is to collect a large number of plastic (PET) bottles and plastic shopping bags. It’s clean and cheap. Moreover, it helps to take care of our environment !

The plastic bottles should be cut in two : a shorter bottom part (the cup, used as a water tank) and a longer top part (with the stop still on), to be filled with potting soil. In order to cut the bottle in two optimal parts, define the length of the two parts approximately so that, turning over the top part (that will contain potting soil later on) and sliding it into the bottom part, the stop is touching or almost touching the bottom of the cup. If this is not the case the bottle will be rather unstable. Then, a small slit should be cut at the edge at two opposite sides of the bottom cup so that the top part of the bottle can be pushed into the cup until the stop reaches the bottom (short slits will open a bit). It is better to have the bottom cup a bit too long than too short (stability). One can always cut the two slits !

The bottleneck should be perforated at two opposite sides, close to the stop, to create drainage possibilities if too much water is poured in the bottle and to create water absorption possibilities from the bottom cup. Holes of 5 mm diameter are sufficient.

When filling up the inverted top part with potting soil, the soil should be well compressed in order to avoid larger air cavities in the bottle. I recommend to mix a water stocking soil conditioner with the potting soil, but if this is not possible for financial constraints, don’t hesitate to do it without.

During the first days, watering should be abundant to eliminate too much air in the potting soil. As the infiltrating surplus of water will run through the two openings in the bottleneck into the bottom cup (water tank), and as evaporation will be limited (only through the top opening of the bottle), one can save a lot of irrigation water and produce significantly more biomass with less water (less leaching of nutrients from the potting soil, and less evaporation).

Isn’t this a nice solution for some of our main environmental problems in the drylands ?
The same advantages are offered when growing vegetables or young trees in the classical plastic shopping bags.

Fill up a plastic bag with potting soil for 2/3, and keep the two handles of the bag upright, simply by pushing them up and sustaining them with two pieces of a small branch or another support (one at each side of the bag). Thus, a shallow cavity is created above the potting soil in which water can be poured from time to time.

Don’t forget to perforate the lower part of the plastic bag a couple of times at the two opposite sides of the bag, e.g. 2-3 little holes (not slits !) at both sides approximately 1-3 cm ( 0.5 – 1 inch) above the bottom (and not in the bottom itself, so that a bit of water can be kept temporarily in the bag). Vegetables can be seeded or planted in the potting soil. Young tree seedlings can also be grown in such a simple plastic bag.

Considerable advantages :

(1) more biomass with less water (because of less leaching and less evaporation).

(2) eliminate plastic from the environment by burying the used plastic bottles and bags at the end of the growing season, e.g. when planting the tree seedlings in a planting hole (ecological cleaning).

Caution : avoid heating in the bottles or bags by keeping them in half-shade or in places where the number of hours of sunshine is limited (not a full day).

Please set up some experiments and discover the real advantages of gardening in plastic bottles and bags, not in the least the provision of food security and the alleviation of poverty. That’s what I call a success story or best practice for sustainable rural development. I hope that once my preaching in the desert will be heard.

PS. Have a look at my former postings to discover pictures and drawings.



“Thank you so much, Prof., for the explanations and the methodological approaches. I will try something in this area. This will really relieve our poor people in the dryland-areas to improve their nutrition. Similarly this will assist in improving the environmental sanitation by giving use values to the plastic bottles that are being thrown everywhere in our cities. Thank you.

Bottle gardening: experiment with Green Ambrosia (Y.PATEL / Willem)

Some weeks ago I received a fertilizer from India, sent by Mr. Yogesh. I promised him to set up some experiments with his “Green Ambrosia“.

Here are the first pictures of the experiment set-up :

Different bottle sizes

Starting the experiment with 3 different bottle sizes. Each bottle cut in 2 parts : 1/3 bottom (serving as a water reservoir), 2/3 top inverted in the bottom part. I leave the lid (stop) on the bottle and make two small openings in the lower part of the come (bottleneck), just above the lid through which water from the bottom tank can be absorbed. (Click on the photo to enlarge it).

3 different bottles with Brussels sprouts

The bottle is filled with a potting mix and a seedling of Brussels sprouts (a cabbage variety) is planted in it.

I am carrying out the experiment with 4 bottles of each size (12 bottles in total) and split up in 2 series :

(1) One series is kept as control (without any special treatment, just leaving the plants growing in the bottles)

(2) One series is treated with the fertilizer Green Ambrosia.

I will publish a report on this after ending the experiment.

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.


TOLLEDOT’s container gardening experiments (Flickr)

News from Joseph TOLLEDOT’s container gardening experiments :

“Here’s the link to new photos on my Flickr page –

I agree with the root growth in the bottles, as you will see. Also, the party cup is excellent – I usually make small holes at the bottom and stand the cups in a tray and water once a day with a small amount of water to keep them just moist. To transplant, you just squeeze the cup a bit and out the root block comes!

I am now working on a cheap, recycled, vertical system which I will photograph as soon as it is set up…”.


Thanks, Joseph, I am looking forward !


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“.

Brazilian rhapsody in PET blue (J.C. Guimaraes)

Today, I received a very interesting comment from Brazil.  Thanks to Joao Carlos GUIMARAES we can now set up some experiments with PET bottles to limit irrigation.  Should this system work well, a lot of water can be saved.  Please read his suggestion to keep the rootball of young trees moistened :

Dear Sir

Since 2 months ago, I  have experimented to use 2 liters PET bottles to make irrigation of baby trees. Where we live, in Brazilian Amazonia, it is now summer season, meaning 6 months dry with high temperatures, until next December.         

It is very simple:

* Just perforate a little hole –  2 mm – at bottom of the bottle.

* Excavate a hole in the soil with the diameter of the bottle,  more or less 20 cm deep, near the roots.

* Put bottle in the hole. Cover side with soil.

* Fill bottle with water before putting it in the hole.

* Close well the  bottle cap. (If you keep bottle open or badly closed, water will infiltrate quickly in the soil).

* When soil is dry, it pulls water from the bottle (via capilarity,  or percolation, or vacuum,  I don’t know  very well).

* When soil is humid, the level of water in the bottle stays almost intact.

* Depending on soil and sun, I  completed the water level once to 3 times a week.

It’s interesting to see that some bottles get deformated, crushed,  because of the vacuum force of soil suction.

Now I’m going to set up an experiment with 2 or 4 bottles per tree. Then, I don’t need to wait for the rain season to plant more trees.

As I said before, this is a new experiment. Maybe others could share it and upgrade it.  If you want some photos of it, I will be glad to send them to you.

Best regards

João Carlos Guimaraes
State of Pará


Isn’t this a marvelous idea ?  I know that, when planting trees in urban areas, perforated tubes are put in the plant pit close to the stem to facilitate watering.  But this quite simple technique to use PET bottles was unknown to me.  Should you know more about it from literature,could you please send me a comment ?

I intend to set up some experiments with this “system for water use efficiency” for our UNICEF project in the Sahara desert.

Looking forward for your reactions.

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).

More successes in plastic bottles (Willem)

Today, I took some new pictures of my trials with plastic bottles.  I feel very happy about the outcome.  This is clearly a fantastic way of growing plants with a strict minimum of water.  I came to the conclusion that this technique belongs to the best practices to grow all kinds of crops in the drylands.  It can certainly play an important role in food security, particularly in regions where irrigation water is scarce.  One can grow vegetables, fruit producing species and even young trees in plastic bottles.

All kinds of plants in bottles
All kinds of plants in bottles (click on the picture to enlarge it)

Wild strawberries
Wild strawberries

Later on, the young trees can easily be planted by simply cutting the plastic bottle open at two opposite sides, bending the plastic wall over to liberate the rootball (to be surrounded with the soil in the plant pit) and bury the complete bottle.

Thus, we can not only recycle the plastic bottles during a certain period, but also eliminate them by simply burying them when planting the young trees.

A nice way to take care of our environment !

Of course, the same can be done with plastic bags.