Hi. Posting from Scotland. My background is in polymer technology and specifically developing hydrogels for medical, controlled release, biomaterials and sensor applications. My hobby is cooking and growing fresh kitchen herbs which I used to water to a fairly strict regime - although sometimes from above and sometimes from below. My plants did ok for awhile but usually then suffered from overwatering.
I decided that I should be able to control the flow of water to plants using my hydrogels in membrane form. After a few prototypes my invention worked spectacularly well with basil, achieving plants 2ft - 3ft in height! I extended it to using common houseplants like begonia, chrysanthemum, poinsettia, orchids, streptocarpus, hedera, areca, peace lily, gerbora, bromeliad and african violets with similar success.

My Osmogro invention uses osmosis whereby water diffuses from a reservoir through a hydrogel membrane into a plant container. When the water reaches the soil it dissolves nutrients and salts within the soil to form a solution which in turn creates an osmotic potential across the membrane. This causes more water to be drawn through to balance the relative concentrations either side of the membrane. At the same time the plant is drawing water and nutrients from the soil and "soil solution" through its root system. In effect the plant is controlling the rate of transport of water from the reservoir through the hydrogel membrane. The worry is taken away about how much? and when? to water as all that needs to be done is to maintain water in the reservoir. The plant then maintains the equilibrium. I've gone from keeping only a few plants, mostly herbs, to having lots of plants around my home. I have an african violet that has flowered 10 consecutive times in 4.5 years. I monitor when I fill the reservoir and can now predict when it is about to flower as there is an increase in water uptake. It is amazing how little water the plant uses, especially as it is now about 12 inches in diameter. I think this has been achieved by removing the lottery of feast and famine watering, whether from above or below. Chris

On Wed, 15 Jun 2005 12:54:30 +0000, Chris_Moran
wrote:

snipped interesting description of osmotic growing system

Sounds interesting. What do you use as your osmotic membrane? When I
did chemistry at school (more years ago than I care to mention!),
osmotic membranes were either a difficult-to-prepare membrane of
copper ferrocyanide, or the cellophane wrapper from certain brands of
cigarette packet (not all worked). Presumably the science of such
membranes has moved on a tad!

Is it any better than supplying water via capilliary matting, which I
imagine also allows the plant to take up only the water it requires?
How do you compensate for loss of salts (nutrients) taken up by the
plant?



--
Chris

E-mail: christopher[dot]hogg[at]virgin[dot]net

[quote=Chris Hogg]On Wed, 15 Jun 2005 12:54:30 +0000, Chris_Moran
wrote:

snipped interesting description of osmotic growing system

Q1. What do you use as your osmotic membrane?

It's a novel hydrogel based on polyethylene oxide. I developed a range of compositions during 20 years research at university. I can make them with different swelling capacities, mechanical properties and optionally biodegradable (to safe components).

Q2. Is it any better than supplying water via capilliary matting?

Capillary matting tends to overwater (by default) and also you get backflow of muddy brown water. A commercial grower did a comparative shelf-life trial and my system significantly outperformed capillary matting trays. You can also keep different plants with different watering needs on the same reservoir like a windowsill tray or similar. Also makes a good holiday watering solution.

Q3. How do you compensate for loss of salts (nutrients) taken up by the
plant?

Salts and nutrients can be replaced in the normal way by using commercial nutrient products as directed. I am also working on some controlled nutrient delivery ideas - I have worked on controlled delivery systems for humans!

Chris Moran

More information regarding the osmogro houseplant watering system and technology is available at www.osmogro.com .

Here is a picture of my first African Violet during its second flowering. It was described as "almost show standard" by the UK St Paulia Society. I think this was achieved because my membrane controlled watering method allowed the plant to establish its own happy and dynamic equilibrium. The 10th consecutive flowering has just started. If anyone is interested I can post a chart of the water useage for the 4.5 years that I have had the plant. The flowering and watering pattern and rhythm are quite clear to see.
Chris

http://i10.photobucket.com/albums/a1...tPaulia06b.jpg

See below charts of my african violet's water usage since I put it on my membrane osmosis watering system at the beginning of February 2001. I've included an exploded chart with clearer detail of the increase in water use prior to flowering.

The plant was originally about 4 inches in diameter. Its peak size was about 16 inches between the second and third flowerings. As it begins its 10th consecutive flowering, the diameter is about 12 inches. The average leaf size is now smaller and more regular than during the earlier flowerings - there are 4 (maybe 5) concentric leaf rings compared to 2 - 3 rings at the beginning.

I think it is interesting to see how the overall rate of water use has decreased as the plant has grown in size. I guess this is due to the larger plant being able to hold and retain more water in its structure. I think that I am also seeing a pattern of 2 flowerings per season. From beginning to end, flowerings last on average 10 weeks.

I have not used any specialist fertilizers, just regular houseplant Miracle Gro Pour and Feed (capful every 2 - 4 weeks directly into the compost). The plant has been re-potted once.

I have kept watering pattern data on many plants including chrysanthemum, begonia, basil, rosemary, poinsettia, hedera (ivy), small conifer, orange tree (from seed), cyclamen and others. They all show variations in the rate of water use (like rolling steps) but differ from the african violet in that the water use generally increases as the plants get bigger.

http://i10.photobucket.com/albums/a1...gPattern01.jpg

http://i10.photobucket.com/albums/a1...gPattern02.jpg

Hope this helps
Chris

Science is busy at big brother HQ this next few weeks,
so a watering can will have to suffice..

Chris, I have just posted my first on this excellent forum asking how to water (and feed) an indoor bougainvillea when I'm away from home for up to a month at a time. I then found this thread of yours and it seems your system could be one of my solutions.

However, bougainvilleas, so I am told, like a bit of feast and famine and so I wonder whether your system is OK for my plant. What do you reckon?

Hi Magellan,
I've no experience with bougainvilleas but I've looked after many different plants with my system. I have monitored water usage over long periods (years) and have seen plants have "resting" periods (decreased water use) and "growing" periods (increased water use). Therefore I would hope it would be ok for bougainvilleas.
Cheers
Chris

Sounds as if is definitely worth an experiment. Will buy through your web site. Thanks...

Chris, I'm pulling this back up to the top again. Your pots are only 13 or 14 cm tall. My plants need 30 cm deep pots as the plants grow up to 30 feet. I have 3 questions...

1 Will your system work with plants that need bigger pots?
2 Have you plans to make deeper pots?
3 If not could I successfully modify your 14 cm pots to make them 30 cm tall?

I like the concept of Osmogro, I just wonder if there are limitations to the size of plants it can handle.

Cheers
Mike

Hi Mike,
Osmogro will work with bigger pot sizes. I am a limited at the moment due to the costs of getting bigger sizes produced - mould costs - but plan to introduce larger sizes. 13cm and 14cm pot sizes are available because the majority of core line houseplants come in or fit this size e.g. chrysanthemum, begonia, poinsettia, african violets, gebera, kitchen herbs, orchids etc, etc. Also good for growing from seeds and propagating cuttings. Good size to get started with as well.

You can make larger sizes by flattening appropriate size pots which have drainage holes only in the base - cut off the "feet" with a sharp blade and make smooth with sand paper or equivalent.

The osmogro gel discs can be custom made to fit underneath any size pot but current swollen gel disc diameter is ~12cm.

Hope this helps
Cheers
Chris

Thanks Chris, that's the answer I hoped for. I will order some of your kit and give it a whirl....