Buried Clay Pot Irrigation
- One of the most studied, and very effective systems uses a buried clay pot full of water to irrigate plants
- The capillary flow of water through the clay walls of the pot is regulated by demand - so little water is wasted
- Highly recommended! For restoration, gardens, landscaping, farming
- Clay pots worked well even in the lowest, hottest desert
- Excellent for seedlings or for starting seeds or cuttings
- Pot rim painted white to reduce evaporation
Getting Started
- Regular red clay pots work well
- Seal the bottom hole with a cork or sealant
- Use a lid with a small hole drilled in it to capture rainwater
- Set the pot in the soil so the rim is above ground
- You don’t want the dirt and leaves to wash in
- Firm the soil around the pot -- and plant
A Long Tradition
- A Chinese agricultural text describes the use of buried clay pot irrigation in China more than 2,000 years ago
- Excerpts from this book provided my inspiration -- writing does speak across time
- I later found work and use of clay pots in Iran, Pakistan, Mexico and other countries
Fewer Weeds
- Another great advantage of buried clay pots (and other deep watering systems) is reduced weed growth
- In one study weeds were cut 87%
- Less work - and less wasted water!
- Buried clay pots have also proved to be very effective when saline water must be used - or when salt is a
problem in the soil
- The steady moisture reduces salt buildup in the root zone and damage
Starting Cuttings
- Double clay pots are ideal for starting cuttings
- The inner pot is sealed and filled with water
- The moisture is maintained in the soil at an ideal level
- BCP are good for starting cuttings in the field as well
Deep Pipe Irrigation
- This method of irrigation was suggested by a traditional system from India - where water was placed in the hollow stem of a dead plant to water deeper in the soil
- Subsequent research found one study and one report from India
- This has been our best system for restoration work -- cheap, durable and very effective
Deep pipe installation
- The pipe may be about 14-16” long, 2” diameter, set vertically
- Small holes are drilled on the plant side below soil level
- A screen lid is glued on to protect wildlife
Deep pipe drip
- Where a drip system can be set up it can also be used in a deep pipe
- Smaller pipes can be used with the emitter inserted in the pipe
No waste
- Little water evaporates because the water is placed in the deep soil
- Little time is wasted because it is fast and easy to fill the pipe
- It works very well on slopes
- It develops large root systems
Excellent Results
- Survival can be good with very little water
- Mesquite trees were started with a total of only 5 gallons of water in the first year
- Not five gallons a week or two gallons an hour
Wick Irrigation
- Wick systems were also described in reports from India
- Wicks were traditionally combined with clay pots to water orchard trees
- After trying several types of wick systems I think this may be the next great thing!
Wick options
- Wicks can be used in a capillary form, where water is wicked from a reservoir to the plant through a raised section by capillary forces (as little as 20 ml day)
- Or in a gravity feed form, with the reservoir above the wick (a hose clamp can be used to adjust the flow rate)
- Wick with clay pot
- With a riser tube in bottom hole
- Capillary wick from buried bottle in plastic tube
More wick options
- Half inch diameter gravity wick with large reservoir
- Installed with treeshelter and wire cages for jack rabbit protection
- Seedlings topped treeshelter at 3 weeks!
Wick Material
- The best material has been old, used woven nylon rope (1/4”-1/2”)
- Fresh woven nylon rope can be used if it is washed with detergent to remove oils - but it is not as good as old rope
- Cotton is used in India, but tended to mold in my early tests
Porous Hose
- This system uses a vertically placed leaky or porous hose section
- It performs a bit like a clay pot--only it is cheaper and smaller
- These hoses are made of recycled rubber and hold up well
- This can be fed by a bottle
- Or attached to a drip type line
- Both have worked reasonably well
- A fast rate hose is needed to work at low pressure
Tree shelter
- Watering into a tree shelter is also effective if the base is sealed into the soil
- This can be done by hand from a hose, water jugs or using a drip type system
Perforated Pipe
- Sub-irrigation can also be done with slotted drain pipe
- The pipe is laid deep in the soil and filled with water using a water truck
- Best for lines of plants - good for landscaping
Porous Capsules
- A modern adaptation of buried clay pot irrigation was developed in Brazil
- The clay is formed into a capsule that can be placed on a water line
- These worked well -- but were more costly to make
Types
- Porous capsule made by gluing two red clay pots together (I would use Gorilla glue now)
- Porous capsules made by a staffer using a beer bottle for a mold
- These are easy to plumb in a system
- Or they can be gravity fed from a bottle or tank
- These are very efficient
- A range of smaller porous irrigation systems are sold for container plants
Microcatchments
- A microcatchment is a specially contoured area with slopes and berms designed to increase runoff and concentrate it
- Rain falling on the catchment area drains into a planting basin where it infiltrates and is effectively "stored" in the soil profile
- Used for millennia - very effective if it rains! But can be easily filled from a water truck if it doesn’t
- Microcatchments can be shaped to look more natural, but do entail disturbing the soil surface
- More appropriate in agriculture - but has worked well on restoration projects.