Frequently Asked Questions
How is it possible to grow plants with such small quantities of water?
Conventional irrigation supplies water hundreds to thousands of times faster than plants can absorb it. The Water-Witch™ is designed to deliver water extremely slowly, adjustable to match the rate plants can absorb. As a result, virtually 100% of the water supplied can be used by the plant.
Can I use any plastic bottle?
Generally only bottles for carbonated (soda, pop, sparkling, fizzy) drinks are sufficiently rigid and have the correct neck thread. However certain non-carbonated water and fruit juice bottles will work. If in doubt, try it!
The What Bottles? tab has a list of brands known to work.
The Water-Witch™ is compatible with the newest European carbonated soft drink bottles with tethered caps. Just cut off the original cap.
Never use bottles that have previously contained poisons or pharmaceuticals.
How many times can the device be used?
The device is capable of being reused hundreds of times. It has no wearing parts or filters to clean.
My bottle is collapsing and the device is emitting water as it does so. What is wrong?
The Water-Witch™ relies on a rigid bottle that can support a small vacuum when it is turned upside down. If your bottle is collapsing either the bottle has been damaged (crushed) before, or the bottle is made of a plastic that is too thin. The "What Bottle?" section of the website has a list of bottles from known brands that are known to work.
Can I find a replacement straw?
The air tube can be replaced by a 4mm/0.16” polyurethane tubing. This is a common size available in hardware stores or online at retailers such as Amazon.
Can I wash the Water-Witch?
The Water-Witch™ can be quickly rinsed with the straw in place. Never immerse in water or allow the straw (or the socket in which the straw fits), to fill with water.
My Water-Witch™ has stopped working! How can I repair it?
Bubbles released from the end of the straw indicate that water is being released. If no bubbles appear no water is being released. The most likely cause is that water has entered into the internal passages during washing, or during an immersion, or due to the fact that the straw is not fitted tightly in its socket. If this is the case, remove the straw, shake out as much water as possible and put the Water-Witch™ in a warm place to dry out thoroughly for at least a week. Once dry, firmly reattach the straw in the socket and use as normal.
Should I keep using the Water-Witch™ on my outdoor plants even when it is raining?
Yes. The water emitted by the Water-Witch™ is insignificant in relation to that delivered by rain.
Can I add liquid fertilizer to the water?
Yes you can. The function of the Water-Witch™ will not be affected, however the presence of conventional fertilizers may trigger algal growth in the bottle which might hurt your plant. So if you add fertilizer monitor the quality and color of the water in the bottle and watch for changes. Specialized fertilizers are under development.
Is it desirable to put the plant under some water stress?
In the case of most perennial plants some degree of water stress is actually helpful to stimulate development of deep and wide roots. If there is water present deeper in the soil, the roots will naturally grow towards it following the water gradient, as long as the leaves have enough light and the plant has sufficient water to grow. If the soil is slightly moist at the top of the root ball this is generally a good sign that the balance is correct.
Annual plants do not benefit from being in water stress.
In certain cases fruit growers also actually prefer to create some degree of water stress to create intensely flavored fruits.
Does the rate of dispensing diminish as the bottle empties?
The rate of daily emission remains constant until the water level reaches the top of the air straw, thereafter it will progressively diminish until the bottle is empty.
Can I use dirty water?
Yes, to a degree - the device is tolerant of dirty water. In case the sediments accumulate within the Water-Witch™, it can be rinsed and reused (do not immerse the device in water).
Can I use any plastic bottle?
Generally only carbonated soft drink bottles are sufficiently rigid and have the correct neck thread. However certain non-carbonated water and fruit juice bottles will work. If in doubt, try it!
The Water-Witch™ is compatible with the newest European carbonated soft drink bottles with tethered caps. Just cut off the original cap.
Never use bottles that have previously contained poisons or pharmaceuticals.
Are colored or clear bottles preferable?
Either colored or clear bottles will work.
Can I continue to water my plants normally in addition to the water supplied by the Water-Witch™?
Yes. Additional water may further increase the rate of growth. However the Water-Witch™ will keep the plant fully hydrated in the intervals between watering, so that the plant will always be ready to use any additional resources in its environment (light, water and nutrients). For most plants a moist rather than a wet environment is optimal, so there is no need to saturate the soil.
Is it safe to use water for plants that has been stored in PET plastic bottles?
Yes. It is completely safe. Carbonated soft drink bottles are designed to contain food for human consumption and are completely safe to refill and to use for plants.
What will happen to the bottle if it becomes permanently buried in the ground after use?
We encourage users to refill and re-use the device. If damaged or no longer needed, the bottle and the Water-Witch™ can be recycled in the same recycling stream as other carbonated soft drink bottles. In the event that they become buried in soil, the plastics in both the bottle and Water-Witch™ are extremely stable, so they will not contaminate the soil as such, but even when intact they are not part of the natural environment.
Can the bottle and the Water-Witch™ be recycled after use?
Yes, they both can be recycled after use! The Water-Witch™ is made from the same plastic as the original bottle lid.
Place them in the normal recycling stream for plastic bottles for Carbonated/Pop/Soda Drinks.
What happens if it freezes?
The Water-Witch™ and bottle will not normally be damaged by freezing.