Clay pot irrigation using ollas is a self-regulating gardening system that provides sub-surface watering of plants, that is simple, affordable, and easy to implement, making it ideal for small farmers and gardeners. Ollas — or unglazed, baked clay pots — are one of the most ancient technologies with evidence of their use being found on multiple continents in pre-modern civilizations with a relatively low-level of sophistication, bronze- and stone-age technologies, and predominantly agricultural economies. Thought to have originated in Northern Africa 4000 years ago, they have been used in China since the first century BC, and are still used in modern times in India, Iran, Brazil and Burkina Faso.
Ollas are great for permaculture because they represent a more eco-centric ideology, fostering a more eco-conscious and life affirming mindset, creating a better vision for the world. In this vision, humans become part of a larger, expanded network, like an interconnected web of life. This is unlike the West’s dominant, hegemonic, anthropocentric ideology, in which humans are at the top of the hierarchy, and nature exists not to be appreciated, understood, or tended to altruistically, but to be used and conquered. This attitude of unrestrained exploitation has led to the widespread destruction of the ecosystem, as our compulsion to exploit and over-extract the Earth’s resources, in the pursuit of short-term gains and glory, has already started to lead the ecosystem, its biosphere, and all the living and complex natural systems within it to exhaustion, and is rapidly bringing about the degradation of nature and environmental decay. Ollas provide a different mode of thinking that can help us to counter these destructive tendencies and savage ideologies, to work sustainably within the limits of natural systems, reduce waste and water consumption, and to better respect the environment and the resources it provides us, and so that we pay more attention how we use them and reduce waste.
The benefits of ollas are astounding, being incredibly valuable in gardens, for edible plant production, and for landscaping. Plants near the ollas grow faster, better, and stronger, making them very useful for plants prone to diseases from over watering, for revegetating areas affected by high-salinity, for tree-establishment, for use in arid climates, or for water conservation. They area also great for containers. They can be made with locally available materials and skills, they do not require pressurized or filtered water supplies, require watering only once every few days or once a week, and are less likely to be damaged by animals or clogged by insects. The much smaller quantities of water used reduces the amount of labor needed for watering. It also deters weeds, as the soil surface remains dry throughout the growing season, preventing surface plants from establishing. Snails and slugs are also easier to manage, as they tend to gather at the neck on the exposed surface, since it is cool and moist, and can easily be removed.
How They Work
Ollas are simple, dried clay pots, often made by hand. They generally have a wide body, a rounded or flat bottom, and a narrow, tapered neck with an opening at the top. The pots are buried in the ground in the root zones of plants, with the neck partially exposed above the soil, and filled with water. This water is drawn by osmosis through the clay and naturally seeps out of the micro-pores in the terra-cotta surface, absorbing into the soil. Osmotic pressure between the clay and the soil provides a controlled, continuous supply of water. Eventually the plants’ roots will grow around the olla and automatically pull moisture when needed. When the soil has become fully saturated, the water seepage stops, and as it dries out again, the water flow commences and re-saturates the ground. Water usage is regulated by the needs of nearby plants, and inherently checks against over-irrigation.
Planting with ollas provides a very high efficiency, in terms of resource consumption, labor expended, and productive yields, delivering water underground and providing sub-surface irrigation directly to the roots. Soil moisture is consistently maintained at full capacity, giving the crops extra security against water stress. This also conserves water, using 50–70% less than normal surface-water irrigation, making it considerably better than drip irrigation, and virtually eliminates the surface-runoff and evaporation common in modern irrigation systems. Water loss due to deep percolation beyond the root zone is also reduced, if not completely eliminated.
Multiple studies in the developing world have demonstrated the benefits of olla irrigation, using less water than traditional agriculture while still maintaining high yields. Trials in India and Zimbabwe found that melons, cucumbers, and beans grown with buried clay pots used much less water than conventional flood- and basin-irrigation. The following tables compare the productivity and water usage of different methods and plant types.
|Method||Productivity in plant kg per cubic meter of water|
|buried clay pot||up to 7|
Finding And Making Ollas
Ollas may be difficult to find in the industrialized world, and could be prohibitively expensive to deploy in large numbers. A few sources produce and sell clay pots specifically for irrigation, one of which is “Growing Awareness Urban Farm” in Albuquerque, New Mexico. Also check out local or online gardener’s supply and country ceramics stores. Whether you buy them or make them, the pots you use need to be unglazed, porous clay pots, although the neck of the olla can be glazed or painted to prevent evaporation. To test your pots for porosity, spray them with a little water. If the surface becomes damp immediately, then they should work. If you have the opportunity, fill it with water and come back after a couple of hours to check if the outside is wet. If this occurs, then the micro-pores should allow enough leakage to wet the ground around it, but not so much that it oversaturates it.
The optimal size and shape of the olla depends on the plants being irrigated, the
density of planting, and the time
desired between refills. In general, a more tapered, flat-bottomed vessel with a large body and a narrow neck should be more efficient due to an increased surface area and increased water spread. The mouth could either be wide or narrow, but a narrow opening reduces evaporation and the risk of contamination. The neck shouldn’t be too long or fragile, but it should be tall enough to apply some surface mulch to cover it without spilling into the opening.
One should match olla porosity, size, and shape to plants’ water needs, root size, and root distribution. Each pot will water the plants within its immediate area. The larger the pot, the greater the area it covers, and the less often you have to refill it. As a general guide, smaller ollas are better for container gardening and automatic irrigation systems, and larger ollas are better for larger containers, outdoor gardens, or tree establishment. For most applications, two- to five-liter sizes should be suitable, although capacities of 5- to 12-liters are useful for irrigating vine crops. If you’re using a stand-alone system, that is – if you refill the ollas by hand, supplying water intermittently – then it’s best to use larger pots. If using an automatic watering system, with a constant supply of water, then you can use smaller ollas.
The Olla Global Bucket System
A more affordable alternative to buying premade ollas is to build your own. Different methods are available, including making them by hand out of wet clay using a potter’s wheel, the coil-method, or plaster of Paris molds. However, the cheapest and easiest method uses two ordinary terra-cotta pots, about 25 cm (10 in.) wide, bought inexpensively from the store. 15-inch ones, for instance, can cost as little as $1 per pot, or less for smaller ones.
Take one pot, sitting upright, and cover the hole in the bottom with a spare tile, a cork, or a wood plug, and seal it with waterproof, silicone caulk or Gorilla Glue. Be careful with the glue you use, as the ingredients in some are toxic, and may not be food safe when exposed to water over long periods of time. Black silicone caulk is the best to use as it is sunlight resistant. If you’re using a piece of tile along with the caulk to plug the hole, be sure to inspect inside the pot for roughness. Rough edges increase the surface area, which increases the effectiveness of the adhesive.
Insert the tile from the inside the pot, and use it to cover the hole on the bottom. Seal it with caulk, press down firmly, and let it dry for 24 hours. If the drain holes are small enough, you can set the pots on a sheet of wax paper, insert the nozzle of the caulk gun into the hole, and fill it up with a small amount of caulk. Let it sit for about 8 hours and carefully peel it from the paper. You can also simply put some masking tape over the outside of the hole on the bottom of the pot, then turn it over and fill the inside of the hole with caulk.
After finishing the first pot, take another one, flip it upside-down, and set it on top of the first one, matching the rims together. Some of the pots may not be completely round, and you may have to try several different pairs before finding a match. Test them again to make sure their rims fit as closely as possible, and draw a pencil mark on the side to indicate the point of best alignment.
Apply a bead of caulk along the rim of one pot, making sure there are no thin spots that could contain air gaps. Gently set the other pot on top, line up the pencil marks, and smear the caulk around the edges with the tip of your finger to smooth it out. The glue should expand when it dries, creating a water-tight seal. To reduce leakage, apply more caulk or glue around the exterior of any holes or edges. Let the caulk set up for 24 hours. If using Gorilla Glue, first dampen the rims of both pots by dipping them in water for about 10 seconds. Apply the glue to one pot, then set it on top of the other, and wait about 60 minutes for the glue to set. Be sure to put pressure on the pots using tape or rock-weights while the adhesive cures.
To test the seals on your ollas after fitting them together, plug up one hole with a finger (if it’s not already sealed shut) and blow into the other. If you feel back pressure building, then the seal should hold. On smaller pots the silicone caulk may not hold well for long, because of the low surface area around the rim of the pot, and approximately 10% of them will fail at the glue joint. To prevent this, try using Gorilla Glue instead of the caulk to glue the pots together. You could also rough up the rims of the pots with sandpaper to increase their surface area.
This same system could be built using a single flower pot with a terracotta plate glued over the opening, and turned upside down. For shallow-rooted plants like radishes, you could potentially modify the shape of the ollas to make them flatter and rounder, by gluing two clay saucers or plates (instead of pots) together to make a disc-shaped vessel. This way you could bury it about 6-inches down in the dirt, and plant in a wide, circular area right on top of it.
The Potter’s Method
You can make your own ollas by hand with wet clay using several methods. However, no matter which one you use, the pots will need to be fired in a kiln, which can usually be found at a clay store, pottery studio, and at a college or university. The pots are made from a mixture of clay and sand at a ratio of 4:1, which will give it an effective porosity ranging from 10-15%. Depending on the clay, you can add, rice hulls, or sawdust at a ratio of up to 1:4 to increase the porosity of the pots. You could also simply add more sand, although using a more crude, impure clay
(which has a varied mix of particulate sizes) will result in larger pores during the firing process. Or, you can mix 20% sand with 20% quality clays, or the same percent of sifted rice hulls or sawdust. After mixing the clay, use a potter’s wheel to mold it into different shapes, typically with a spherical or round body and a flat bottom. The pots are then tempered by baking them at high temperatures.
Firing the ollas makes the clay hard and strong, while still allowing water to pass through. The temperatures required can vary, depending on the quality and mixtures of your clay, the type of oven used when baking, and your desired porosity, and could range anywhere from 200° to over 1,000° C. Small-scale, earthen-ware manufacturers generally temper their ceramic pots at 1200° C. A course, red clay with sand impurities and a mixture with 20% or less of straw should be fired at around 800° F, or around 430° C. Closed-oven firing at temperatures exceeding 450° C are ideal. Generally, the pots should not be fired much above 1,000° C, or their porosity will be limited. Adding more grog (ground old ceramic) will increase porosity by burning out the filler, leaving uniform pores and a high-quality pot. It is important to find the optimum temperature for your pots. If you make it too hot, the clay will become water-tight, making the ollas useless for our purposes. However, if the pots are not heated enough, then they may breakdown in the soil, causing leakages.
This method builds the pot piece-by-piece, in layers from the bottom up, by laying long, rolled coils on top of each other around the sides of a bowl or plate to build the pot. Begin by pinching a ball of wet clay to create a bowl-shape. Use this as the base of your olla, and build up around it from there. Or, you can take the bottom of an old, terra-cotta plate (puki), and lay down a tortilla-shaped piece of clay on top of it. Then, roll a lump of clay between your palms, creating a long clay rope of uniform thickness, and form the base of the olla by pinching and pressing this coil onto the sides of the clay tortilla with one hand, while turning the bowl or puki with your other hand. Add successive layers of coils until the vessel is completed.
The Casting Method
You can also make the jars out of a mold-casting. This is an excellent way to mass-produce ollas if you can successfully cast them. To make the urns, create plaster of Paris molds from pumpkins, squash, or gourds of various sizes. Then pour liquid clay into the molds to shape the urns, and fire them in the kiln to solidify the clay.
Using Milk Jugs as Ollas
You can also repurpose some used 1-gallon milk jugs to turn them into artificial ollas. Take your empty milk jugs, fill them with water, and freeze them overnight. Poke multiple small holes into the sides of the jug with a nail or ice pick and hammer. When planting near a wall or walkway, you may want to poke holes on only two sides of the jug, so that the water flows to your plants and not on your pathway. Bury the milk jugs, plant, and water in the same manner as the ollas.
Burying and Watering The Ollas
Start by digging a planting hole about three times as wide and twice as deep as the clay pot. If you encounter clay in your topsoil, discard and replace it with finer, higher-quality soils, as it makes it hard for the water to penetrate. In very heavy soil, you may wish to add sand or gypsum to improve its characteristics. In either case, you will want to fertilize the soil to add more nutrients for the plants. Simply take half of the soil you just removed, break it up using a spade or fork, and add it back into the bottom of the pit. Take the other half of the soil and mix in 1/3 of compost, aged manure, fertilizer, or potting mix with dolomite.
Before burying the ollas completely, it’s best to first fill them and check for leaks. Once that’s done, place the pot in the pit on top of the loose soil, and fill the pit around it with the fertilizer-soil mix. Then bury it up to its neck so that the top is about 2 cm above the surface of the surrounding soil. The top of the clay pot should remain exposed above ground so it can be refilled. To make the top of the pots easier to see, and to reduce evaporation, paint the top rims with white paint. The upper body of the buried clay pot can also be partially painted to reduce water use, but be sure your paints do not include any harmful materials, such as lead or cadmium.
When finished burying the pots, put mulch around the exposed neck at the surface to reduce water evaporation. Then, fill them with water and put a cover over the opening. Keeping the mouth of the jar fully covered prevents insects, animals, and debris from getting inside, in addition to reducing water loss through evaporation. If there are no fitted lids for the jars, you can use corks, plastic lids, cups, metal dishes, flat rocks, clay plates, shells, ceramic tiles, or even pot holders, depending on the size of the hole.
Water takes between 24 and 72 hours to flow through an olla. Depending on factors such as the plant’s water needs, pot size, soil type, time of year, and environment, the ollas may need re-filling every 2 to 3 days for small pots, or once or twice per week for larger ones. To keep the system working optimally, add more water to the pots as needed, and avoid letting them get completely dry. In order to avoid build up of salt residues along the inside surface of the olla that may prevent desired seepage, add water whenever the water level in the olla falls below 50%.
Domestic water effluent, or greywater from kitchens, can be used to refill the pots. Although, it should be filtered first, or otherwise it will clog the pours. You may also supply the olla with water mixed with liquid fertilizer. Simply mix the fertilizer or compost seed in the water, and use it as normal. The liquid fertilizer is more expensive than the granular kind, although, with the liquid variety, you’ll only need about 1/4 to 1/2 of the amount (per unit area of land) compared to granular fertilizers. This is due to the tremendous efficiency of the delivery of nutrients directly to the plant’s roots. Do not add this too often, however, as particles could build up and clog the pours in the clay.
Planting With Ollas
The system is useful for annual and perennial plants, woodlots, and horticultural, orchard or plantation crops. Tests and research conducted around the world — including China, Pakistan, India, Mexico, Brazil, Iran, California, Arizona, and New Mexico – have found that the following plants are suitable to use with clay pot irrigation:
- Bee Balm
- Collard Greens
No research seems to be available on the consequences of using ollas in a dense polyculture. However, many other intercrops should work well with buried clay pots. The Fan Sheng-chih Shu, an ancient Chinese text describing clay pot irrigation, recommends planting 10 scallions around the pot, interspersed with four melon seeds, and to harvest them in the 5th month as the melons begin to ripen. Lesser beans can also be planted in with the melons and scallions. If growing root vegetables, like potatoes, then bury the ollas a bit deeper in the soil.
You can plant from cuttings or transplants, or you can raise seedlings in situ instead of transporting them from nurseries. However, ollas are not very good for seed germination, as there won’t be enough surface moisture to water them. A small amount of water should be added to the seed spot or transplant to help wet the soil and establish capillary action from the buried clay pot. If starting with plants that already have roots, water the surface until their roots grow low enough to establish themselves. If planting with cuttings, try setting up a double clay pot to propagate them. Take a sealed pot and set it inside a larger one with an open drain. Fill the space between them with sandy potting mix, and put the cuttings in there. This way, they will be kept moist but still get oxygen.
It has been noted that plants with thick roots, and those with woody perennial plant root growth, will likely grow right through the pots and break them. This makes the pots less useful for long-term tree irrigation, but they can still be used for system establishment. Trials in Pakistan using 8-inch clay pots, refilled every two to four weeks, showed that tree seedlings irrigated with buried clay pots had a survival-rate of 96.5%, compared to 62% for hand watering. The seedlings grown with buried clay pots were also 20% taller. After eight months, all tree seedlings grown around the pots were alive and well, while all of the trees irrigated with the same amount of water using basin irrigation had died. Examination of the root distributions showed that several roots had wrapped themselves around the pot, while two dominant tap roots went straight down to considerable depth. This shows that buried clay pot irrigation can help develop a sufficient root system for long term survival and permanent installation of fruit, nut, and desert trees like pistachio, mesquite, acacia, or eucalyptus. The pot only needs to be filled regularly during the first year and can then be removed.
Be careful when producing fast-growing and spreading plants, like squash and melon vines with big leaves, as they may not be able to get enough water in some situations. Some sensitive species of plants could also be prone to pest or disease because of the constant levels of moisture in the soil. Heavy rains could exacerbate these problems when too much extra moisture is added to the garden. Beware of plants with invasive root systems, as they can grow out horizontally to steal water from the ollas.
When planting with ollas, there is the potential for breakage if left in the ground in areas with a winter freeze. In temperate climates, dig the pots up at the end of the growing season to prevent breakage. Burying the pot further underground, about 4-inches or so under the surface, may help protect it from freezing. The longevity of most ollas (without frost) is unknown, but estimated to be 2- to 5-years, depending on the quality of the clay, the mineral content in the water, and soil temperature swings. Prolonged use is likely to decrease porosity and clog up the pots over time. If this happens, soak the pots in water and scrub them clean, or re-fire to clear out the pores.
The correct spacing of your plants will depend on the shape and size of the ollas, and of the crops you’re growing. Not much research is available as to the optimal spacing of plants around the ollas, but some women in the developing world used clay pots with a capacity of 5-liters each, and buried them at 0.5 m intervals in prepared seed beds. Ancient practices buried many pots on large swaths of land, using 530 pits per hectare (210 pits per acre), with each pit being 70 cm (24-inches) across and 12 cm (5-inches) deep. To each pit was added 18 kilograms (38 lbs.) of manure, and mixed well with an equal amount of dirt. An earthen jar of 6-liters (1.5-gallons) was buried in the center of the pit and filled with water to the brink.
Pots of about 1.5-gallons will seep water out to about 18-inches. The general rule of thumb is that each olla will water outwards at a distance about the same length as its radius. For optimal water utilization, arrange the pots in clusters, separated from each other at a distance equal to the width of their diameter or more, and plant in circles around them within about 18-inches around the base of the pot. In general, place your pots about 3 m (9-feet) apart for vine crops, and 1-1.5 m (3- to 5-feet) apart for corn and other tall-growing plants. The seeds or plants should be placed no less than about 1/2 of the radius away from the edge of the pot, and no more than the length equal to the diameter away from the edge, to maximize water absorption. It is helpful to leave a space between plants on one side of the pot to make it easier to lift the lid and refill it as the plants grow larger. You can also use pots in raised beds and containers. Simply use the 1-radius rule to find out how large your containers and beds need to be.
Self-Filling Gravity Fed Irrigation System
You can modify your clay pots to implement an automatic watering system by planting them in a series, connected by black irrigation tubing, and attaching them to a gravity-fed barrel or bucket with a fill valve to keep them continuously watered. One advantage of this system is that you can run it down the length of a fence, making good use of a small, otherwise unused space.
- ¼-inch or ½-inch black poly tube
- ¼-inch plastic T
- ¼-inch x 1 ¼-inch Fender Washer
- Silicon Caulk and Gorilla Glue
- Waterproof Plumbing Epoxy Putty
- Terra Cotta Pots
This automatic filling system keeps the ollas constantly filled with water by gravity-feeding down into the capsules. All the ollas are connected together in a linear series, with a common reservoir, via black polyethylene irrigation tubing, available at Garden Supply stores. This tubing is useful because of its low price and resistance to UV radiation. Alternatively, you could wrap a clear piece of tubing with electrical tape to make it sunlight resistant.
Get a plastic, 5-gallon bucket with the lid. The bucket should be opaque or painted black on the outside to block sunlight and prevent algae growth. This will serve as the reservoir or regulator to control the water flow, and maintain the flow rate into the capsules. In order to keep the flow rate constant, and maintain water pressure, the water level in the bucket should remain constant. Every 28-inches of elevation in the difference between the height of the water and the top of the capsules will add one pound per square inch of backpressure. Higher levels can be used to help prime the system more quickly, and lower levels can be used to conserve water when the plants don’t need as much. Regulate the flow of the system by changing the water level, or by raising or lowering the bucket.
A toilet fill valve, bought from the hardware store, can be used to maintain the water levels in the regulator. The particular toilet fill valve you use will determine your next step. The valve should be connected to the bucket via a hole, drilled in the bottom or in the side, and should either stand vertically, rising from the floor, or dangle inside. If it is an evaporative cooler valve, or a float valve (which consists of an inflated bladder that floats on the surface and lowers with the water level), then you should drill a hole into the side of the bucket, near the top, and install it there. If it consists of a central, vertical shaft (like the toilet-fill valve), then flip the bucket upside down, and make a mark on the bottom of the bucket, about half-way between the center and the rim. Drill a hole to match the sizing of your fill valve, which should be about 1 1/8-inches.
Next, insert the fill valve into the hole you made, and screw on the nut from the outside to seal up the washer. You want the tapered part of the washer on the fill valve to fit just inside the hole so that it centers up. If you have a vertical fill valve, then adjust the length of the toilet fill valve to match the height of the bucket, which should be about 13-inches or so for a 5-gallon bucket. If you have an inflated bladder, then the height of the hole you drilled in the side will determine the maximum fill level. Adjust your fill valve fittings to try to get the maximum amount of water in the bucket when it’s filled. But don’t make it too high, as there needs to be some clearance between the top of the fill valve and the lid.
Orient the valve so that it’s pointing roughly towards the center. Attach the other nut which comes with the valve assembly to the tube. Get about a meter-long length of some 3/8-inch black plumbing tubing, and screw it on to the valve. Hold on to the end of the tube with one hand, and orient the tubing so that the curve is pointing away from the bucket. Now get a dishwasher elbow, like a Watts A-158A model, which has a compression fitting with a hose fitting on the end. This allows you to attach a garden hose with the tubing going in the other end. First loosen the compression nut, and then push the tubing into the hole. Grab the thin part of the attachment with a pair of pliers, using the same hand, and tighten the nut with a wrench using the other hand, making about 1 ¼ turns or until snug.
To get the water out of the bucket and down to the olla capsules, you need a header tube, which is the long tube that feeds the whole system. You can use ¼- or ½-inch tubes, depending on what system you’re using. If your system consists of a long, single piece of tubing that extends out into the middle of the bed, with multiple ¼-inch tubes leading out to individual ollas, then use the ½-inch tubing to accommodate a greater water capacity. If your ollas run in a circular chain or circuit, in which small pieces of tubing run through and out the opposite side of each olla, then use ¼-inch tubing. With this system, five to fifteen ollas can share the same ¼-inch feeder tube. Whichever system you use, bury your olla capsules about every 24- to 36-inches down the length of your garden.
Drill a hole into or near the bottom of the bucket, slightly smaller than the diameter of the tubing. Once you’ve made the hole, you can shove the tube right inside. The tubing should grab onto the sides of the bucket and stay in without leaking. If you want, you can put the tube through the hole, and then put a barb fitting over the end of the tube, or rough up the edges on the end a bit and use Gorilla Glue or black caulk to seal it. Get a secure seat, a steady rock, or build a wooden frame, and set the bucket on top of it so that the bottom is placed at, or a little bit above, garden-soil level. Cover the reservoir bucket with a lid to keep mosquitoes out.
Next, get some small clay pots, about 2 ½-or 5-inches wide, seal the holes in the bottom with black caulk, and glue them together with Gorilla Glue to create an olla capsule. The size of the olla doesn’t matter so much, as long as you can feed water to it continuously, although smaller-sized ones are better for automatic irrigation systems.
After putting the pots together, use a drill press, with a 7/32-inch carbide or concrete drill-bit, and make two holes opposite each other on the sides of the pot, just below the top ridge. The holes should be perpendicular to the side of the pot, and angled slightly downward. To get the correct angle, place a block of wood or metal under the pot to prop it up and hold it steady.
Drilling the holes in the sides allows you to hide the tubes just under the soil, protecting them from accidental damage. If you’re using a system with a single large header tube, then drill one hole in the side and another in the top to allow air to escape. In the top hole, insert a tube and cut it so that it’s sticking out by about 6-inches or more. Ensure it points upwards so that water doesn’t spill out, and so you can bury the pot a little bit deeper if you want. To seal this breather tube, and to keep the bugs out, use a small, cheap plastic plug from the hardware store.
Next, cut some pieces of the ¼-inch tubing, each about 24- to 36-inches long, and insert them in the holes. To help the caulk adhere to the tubing, roughen up the end of it with some sandpaper, apply a thin bead of Gorilla Glue or grey epoxy putty around the tip, about 1/8-inch from the end, and then insert the tube into the hole. You may find water leaking where the tubes enter the holes. This may be because the silicon caulk didn’t adhere 100% to the slick tube. You can experiment with different glues or tubes to solve this. If your ollas are running in a circuit, so that each olla is connected to another, then connect them together with the tubes. If you’re using a main header tube, then attach the watering tube that runs from the olla to the main tube, leading from the reservoir, and connect them with a plastic T, or another connection fitting.
Another method uses the one hole in the top of the pot. Take two pots, seal up the hole in one (leaving the other open), and put them together as normal. Then, take a plastic T, two pieces of tubing, and a metal washer. Put the metal washer over the downward spout on the T, and glue them together with silicon caulk. Next, wrap a band of grey epoxy putty around the downspout, leaving a hole in the middle to allow water to flow out, and stick it inside the hole in the pot. Lastly, drill a small hole in the top of the olla to insert a breather tube.
Coke Bottle Watering Globes
To make your own recycled watering “globes,” take an empty glass bottle, fill it with water, and quickly slam the open end down into moist soil near your plant’s roots. The air inside the bottle should create a low-pressure vacuum, keeping the water from leaking out too quickly, and slowly releasing into the ground. If you see bubbles rapidly forming, or the water level changing, suddenly, then the bottle-mouth opening may not have sealed against the soil. Pull the bottle out, re-fill it, and try it again.
This works the best when the soil is already damp, so water the plants a bit first, and then add the bottles to the planters. If the soil is hard, or there are rocks in your medium, there’s a chance the bottle could break. Consider using heavy gloves to prevent injury. If you have an extremely thirsty plant, or are going to be gone longer than a couple of days, use a larger bottle, like a wine or whiskey bottle.