Frequently Asked Questions

How To Use TreeDiaper®

Place TreeDiaper on top of soil and make sure the bottom of TreeDiaper touches soil surface. Apply mulch on top of TreeDiaper. Placing TreeDiaper on top of mulch will reduce the water transportation efficiency.
Covering TreeDiaper with fine-particle materials such as dirt, fine sand, and compost should be avoided, as they will block rain water from reaching TreeDiaper and affect the functionality of TreeDiaper.
The best method is to allow rain and snow to naturally refill your TreeDiaper®. You can also recharge your TreeDiaper® in bucket overnight or for 5 hours. We recommend customers install TreeDiaper® 2 months before rainy season is over for the best results.
You can also use a water hose on TreeDiaper® for 15 minutes, but keep in mind that our product does not absorb water as quickly as the water hose dispenses it, so this may not fill your TreeDiaper® completely. Most of the water will run off when you use a water hose. Recharging TreeDiaper® in bucket or watering it for 2 minutes a day for a week will work better than a 15-minute block of watering. If your region is in severe and long-term drought, you may use drip irrigation in combination with TreeDiaper®. It saves much more water than drip irrigation alone and will help you to catch some rainfall during the rainy season.
This is not recommended. Using only part of our product will result in an uneven soil moisture distribution; the product will not work as intended. However, strategic placement for special purposes is possible and will be further explained in the next FAQ section.
We first received this question from Maggie and Tom, two consulting arborists from Montana. Tom and Maggie hoped to promote root growth in the direction from which wind came primarily. Longer roots in that direction would help to stabilize trees against the wind. We believe that this goal could be achieved and would work best with the 4-piece TD48 (or multiples of TD48) by arranging the pieces in a configuration to provide more water resources on the preferred side.
TreeDiaper is designed for younger trees but it can be used with plants of all sizes and ages. For a dry TreeDiaper, we recommend installing it two months before rainy season is over so that it can be charged with natural rainfall. It is best to fill the TreeDiaper with water by soaking it in a bucket before placing it on your plants, especially if you are installing it during a dry season.
Yes, it has been done many times. This case study was a retrofitting project. Trees were planted in the winter of 2012-13 or the spring of 2013; TreeDiaper® treemats were used to replace watering bags in August 2013. Mulch was not applied originally, so we added mulch to the top of the TreeDiaper® after damages from a lawn mower were spotted.
If mulch is already in place, please remove mulch first, then place TreeDiaper® on top of soil. Be careful to not place soil on top of TreeDiaper®, which may block rainwater from reaching water absorbing pellets inside the TreeDiaper® treemats.
Leave them outdoors; there is no need to take them inside. The rainy/snow season in many parts of North America will charge your TreeDiaper® so they will be prepared for spring time.
Definitely; it saves even more water when coupled with irrigation. Check out our nursery field tests to learn more.
No, freezing and thawing won’t cause any damage. We have used TreeDiaper® year-round since 2013 in central Virginia area without encountering any problems.
In Richmond, there are quite a few winters with single digit temperatures. It is not like the -30s in Midwest. But guess what, a warmer ice has larger volume than a colder ice with the same mass. In another way to say it, H2O expands when it freezes, but it doesn't expand more when temperature gets colder. So the -30s temperatures in Midwest is not going to cause more damage than the freezing temperature in Richmond Va.

We highly recommend leaving TreeDiaper outdoor so that it can charge with melting snow and ice water. It can protect tree roots from winter damage. And it can also promote root growth during winter time. Yes, trees grow roots in winter time.

Additionally, winter drought may kill your deciduous tree without a sign. By the time you notice it, it is too late. Leaving TreeDiaper® outdoor helps to prevent winter drought damages.
It depends on the type of fertilizer. Burying fertilizers in soil under TreeDiaper® is not an issue. Most organic fertilizers are fine. Here are some individual fertilizers that may be considered:
N: Urea (the largest agricultural nitrogen fertilizer) such as Ammonium and Ammonium Nitrate are fine.
P: mono-ammonium phosphate, di-ammonium phosphate and ammonium phosphate. At high concentration, it may temporarily reduce water holding capacity but functionality will return quickly.
K: Potassium Chloride, Potassium Sulfate, and Potassium Nitrate. At high concentration, it may temporarily reduce water holding capacity but functionality will return quickly.
Try to avoid fertilizers or additives containing metal irons other than Group I (Alkali Metals) such as Aluminum, Iron, Calcium, Magnesium, which are common in many mixed type fertilizers.
Yes, but we do not recommend smaller models of TreeDiaper® products for palm trees because of the relatively larger caliper compared to other plants of the same crown size. The larger models (TD36 and TD48) come in multiple pieces that can go around the large trunk easily. The TreeDiaper® 36 treemats are made of two halves and they can be separately placed around the palm trees. TreeDiaper® TD48 treemats consist of 4 quarters and can be placed around the root system of palm trees of any size. We recommend covering not only the rootball, but also the larger area beyond the rootball to encourage outward root growth.
The best way to determine when to recharge or water your tree is to let the soil moisture tell you. How frequently you need to recharge your TreeDiaper® will vary depending on the water consumption of the tree roots and the weather. If your region has much less precipitation, we recommend you check on your tree every two weeks. Generally, TreeDiaper® only needs to be watered once every month if there is less than one inch of rain.
Mr. Gordon Mann (RCA# 480), who has been recommending TreeDiaper® to his clients since 2016, suggests California customers to get 25-33% extra TreeDiaper products and keep them soaked in containers. Send crews to swap dried ones with soaked ones every two to three weeks. TreeDiaper® also works well with drip or sprinkler irrigation systems which can help save water.
For most east coast customers, we have field tests in Central Virginia that have never been manually recharged after the first day. Check out this case study.


Can TreeDiaper® Be Used For My Unique Needs?

A Californian arborist first asked this question during 2018 ASCA annual conference. We ran some tests with a propane torch:
Shortened Version
Full length
A dry TreeDiaper will burn because the fabric is made of polypropylene. For the charged TreeDiaper®, fire and heat damaged the top fabric, but the water absorbing pellets didn't burn. TreeDiaper® will help protect the lower part of tree trunk and tree roots from getting too hot. It will give them a better chance of surviving and bouncing back. While we do not know how this test compares to wildfires in California, by looking at the pictures of the most recent wide fire, the damage is more significant than what we can test with a propane torch.
We have received this question from consulting arborists wondering whether TreeDiaper® would protect roots from winter damage. The answer is yes! In a winter blizzard in 2014, we measured the soil temperature at 3" deep. It remained above 40 F all the time, even when the air temperature dropped down to single digits.
In addition, winter weather won't hurt TreeDiaper® at all. It freezes and thaws without damaging the functionality of TreeDiaper®.
Yes, this is one of the many recommended ways of using TreeDiaper®. We recommend TreeDiaper® diameter be roughly double the rootball diameter. By watering the surrounding soil, it promotes root growth outward. For a newly planted tree, “establishment” means new roots have extended into the surrounding soil of the new environment. TreeDiaper® will help speed up establishment of newly planted trees.
Watering only the rootball or dumping water onto the rootball is a bad practice because it promotes circular root growth or enhances existing circular root growth.
The single piece TreeDiaper® products are meant for very small trees. If the right size of TreeDiaper® is chosen, there should be plenty of space between TreeDiaper® and tree trunk. For example, the TreeDiaper® 24 treemat has a 4” inner hole. It is only recommended for a tree of 1” caliper. The typical rootball size of such trees is about 10-15" diameter. TD24 will cover portion of the rootball, and a large portion of surrounding soil. We are strongly against using TreeDiaper® to cover only the rootball, unless it is in a container. Promoting healthy outward root growth is one of major advantages of TreeDiaper® over other products such as watering bags. Even after the tree grows to a 4” caliper, the TreeDiaper® can be pushed back naturally without wrapping around the tree trunk.
This particular question came from a person who thought the 24” TreeDiaper® meant for a tree with 24” rootball, which typically has 2-3” caliper. For trees of 2-3” caliper, we recommend TD36 and TD48, which have 12” inner holes and are made of more than one piece so that they can be placed further away from the tree trunk.
It depends on the temperature, humidity, wind, and many other factors. In our laboratory tests, TreeDiaper® usually lasted about 45 days before drying out.
It depends on the size of the product. TreeDiaper® has a 0.3-30 gallon capacity with dimensions of 10 inches to 48 inches. Do not compare this volume of water to the volume in other watering methods as the water use efficiency is much different.
The water in the TreeDiaper® is slowly released to plant roots. It increases water use efficiency. In addition, the losses are minimized with reduced evaporation, less competition, less percolation loss, and reduced runoff.
It depends on how much rainfall you have in your region. In one of our case studies from Virginia, roadside trees (https://www.treediaper.com/casestudy-richmond.cfm) installed with TreeDiaper® went for many years without watering. All are still alive, as of May 2018. During this five-year period, there were several seasonal drought conditions, which killed all the trees in the next block, which was captured by Google Maps Streetside Image.
If your region has much less precipitation, we recommend that you check on your trees every two weeks, but it is likely that you will only need to water them once every month, even if there is less than one inch of rain.
Depending on the evaporation rate and rainfall in your area, you may want to check once every two weeks to make sure the soil is moist. If the soil gets dry, water them with a watering truck for 15 minutes.
We typically make recommendations based on the trunk diameter (caliper) because it is generally used by growers to refer a tree size. It depends more on the diameter of the rootball, which is more difficult to determine. The basic concept is to cover part of the rootball and then cover a larger area of soil surrounding the rootball. In this way, the rootball will receive water for the immediate needs of the tree. The surrounding soil is also watered to promote outward root growth.
TreeDiaper diameter should be twice the rootball diameter.
The rootball size and caliper of trees are not closely correlated but there are some general rules about it. For example, UFL has a chart about the estimated rootball size for trees of different caliper: https://hort.ifas.ufl.edu/woody/root-ball-dimension-chart.shtml
It is very common that a tree is planted in a very limited space, especially for urban forestry and roadside plantings (Right of Way “ROW”). In this case, we recommend the largest possible TreeDiaper size for the space. Same suggestion for container plants, where TreeDiaper sizes are limited by the opening diameter of the container.
The conventional methods of watering trees (including using watering bags) do not account for runoff water, evaporation and weed competition. Dumping water on the root ball makes the growing conditions like those in a container and in a nursery. Trees are not encouraged to grow roots outward into the surrounding environment to find water. TreeDiaper® Advanced Hydration System reduces runoff, reduces evaporation, eliminates competition, and encourages outward root growth. With all these features combined, we found trees are able to to survive seasonal droughts without watering or with very little watering.
The biggest difference between the typical method of using hydrogels and TreeDiaper® is that our product reduces storm-water/irrigation water runoff. Conventionally, hydrogels are mixed into the soil. For surface irrigation methods and natural precipitation, water has to penetrate a certain depth of soil before reaching hydrogel particles, so it does not reduce runoff. Hydrogels increase soil moisture, but only when there is enough water in the first place (recent rainfall, irrigation), which defeats the purpose. Hydrogels in soil neither reduce evaporation nor eliminates weed competition. Sometimes, hydrogels can compete with plant for moisture, like desiccants.
TreeDiaper® Advanced Hydration System uses hydrogels to catch, store and slowly release water back to root system. It does not compete with root for moisture. Instead, it releases water into soil so that the plant can use it.
TreeDiaper® won't solve the drainage issue in heavy clay soils as TreeDiaper® is placed on top of soil but it can mitigate some of the root rot problems by absorbing the excess water that is not drained off quickly and reducing the amount of water in the soil. TreeDiaper® will be able to absorb excess water until it is fully filled with water.
If the drainage issue is due to topological features on the ground, we recommend creation of drainage channels or tunnels to let the excess standing water out. If the poor drainage issue is due to the intrinsic feature of clay soil, TreeDiaper® can be a great resource as mentioned above.
Moisture retention by TreeDiaper® is the best among all different types of irrigation technologies. Because the water stored in TreeDiaper is not free flowing and is not in the porous sandy soil, the loss to subsurface is minimized.
Below are five reasons why we claim TreeDiaper® is the best irrigation technology for sandy soil:
1. Slow release of water => Minimizes percolation loss
2. Reduced evaporation => Dries slower from top
3. Rainwater harvesting => Self recharging whenever there is precipitation
4. Weed control => Reduces loss through competition
5. Waters not only the rootball, but also the surrounding soil => Healthy outward root growth => Faster establishment.
Yes, it is the best watering method for plants on a slope. The problem with slope is that water runs off too quickly. With the super slow release function, it does not give water in a free flowing form, so you will lose less water because of the slope.
Water is released from TreeDiaper in multiple ways: osmosis transportation, gravity, and through water vapor transportation.
When TreeDiaper is covering the soil, the rate of evaporation is reduced significantly. The soil profile drying is predominately due to the root uptake of water. As this resource is used, the TreeDiaper releases water into the soil.
Gravity draws free-slowing water out TreeDiaper and into the soil naturally.
There is always vapor-liquid equilibrium maintained in the small cavities between TreeDiaper® of soil surface. When soil is dryer than TreeDiaper’s water absorbing pellets, water releases from TreeDiaper® and then the vapor condenses on the soil surface. This action can be reversed when soil is wetter than TreeDiaper® water absorbing pellets.
An interesting fact: One ASCA member pointed out that condensation under concrete sidewalk is one of the reasons small tree roots tend to grow there. When the roots hit the opposite side, it grows much faster and causes the damages to the sidewalks.
TreeDiaper® wasn't designed to catch water from a faucet or hose. TreeDiaper® was designed to catch raindrops during rainfall and melted water from snow.
Here is calculation of inches of water per unit area of a water hose compared to a rainfall.
To recharge faster than a typical rainfall, one can place in a bucket or container for 5-12 hours. Warm or hot water can will speed the process up slightly. This is known fastest way to charge TreeDiaper®.
Yes, we demonstrated this in our tabletop test here.
This is what we observed. Soil penetration speed is dependent on the soil type. In clay soil, it is faster because the pores are smaller (it takes less water to fill the gaps). In sandy soil, it is slower (bigger pore sizes and it takes more water to fill). In both cases, the moisture reached deeper than 6" within 2 days.
We also have customer endorsement regarding this particular question.


How To Manage Damage

It depends on a lot of factors like soil type, site, slope, rainfall, and surrounding vegetation of the particular location. In Central Virginia, we have had field tests on road medians and in parks since June 2013 where we never watered the trees after the first day. There were drought periods where there was only 0.25” rain at the site over a time period of 7 weeks.
We monitored the soil moisture, which is the best indicator of whether tree needs watering or not. In our case studies in central Virginia, the soil moisture has never reached a below 3 (on a scale of 1-10 with 1 being bone-dry and 10 be soaking wet), so we never need to water them. In this case study, we recorded soil moisture for a long period of time. In another case study, we looked at the signs of stress during a 5-week drought.
We understand there are many water prescriptions across the continent telling people how many gallons of water per day. We discussed this with Professor Gilman (University of Florida), whose work is the mostly cited by these water prescriptions. The water prescriptions do not take account of evaporation, runoff, weed competition and other losses that reduce watering efficiency. TreeDiaper® technology offers much higher watering efficiency by reducing runoff, evaporation and weeds.
For western US, customers who worry about watering amount in TreeDiaper® may choose larger sizes or place more than one units around each tree to ensure there is enough water and reduce the frequency of watering (or swapping dried TreeDiaper® with soaked ones).
Unless it cut wide open and all the water absorbing materials are gone, it should still function to a certain degree. Slightly damaged TreeDiaper® products will provide the majority of the functions. You may cover a damaged TreeDiaper® with mulch and continue using it.
Mix leaked pellets up with soil. They are agricultural grade and will do no harm to the environment.


Special Situations

Lots of people tell us our product's name is silly! The truth is, we chose "TreeDiaper®" because of our dedication to developing new ways to keep the planet green. Did you know baby diapers are currently not recyclable? Think of how much waste this contributes to landfills!
Our founder, Hailing Yang, used this as her inspiration. TreeDiaper® is made from similar materials to baby diapers, so we hope to use our technology to recycle baby diapers in the future, thus eliminating waste. In fact, special versions of TreeDiaper® products made with recycled baby diaper materials are available.
In the United States, it is not illegal to collect rainwater with TreeDiaper®. Only four states in the USA have laws regarding rainwater collection. None of regulations apply to the manner in which TreeDiaper® catches, stores and uses rainwater. If you are concerned, we recommend checking with your particular area.
Unlike watering bags, we recommended TreeDiaper® to be buried under mulch and not exposed to sunlight. Therefore, it will not heat up much. TreeDiaper® also serves as a heat sink for the tree root system which prevents root damage. Similarly, it protects tree roots in harsh winter weather.
In our field tests in central Virginia, we did not notice fungi-related problems. In wet and warm weather, mushrooms are seen everywhere, but there are no fungi-related problems underneath TreeDiaper®. We also have not experienced any problems with bugs.
Yes, roots can get oxygen through TreeDiaper® because there are air pockets and air tunnels in TreeDiaper®. It allows oxygen to flow naturally. Root rot may have many causes: fungi infection or lack of oxygen. But the main cause is poorly drained or overwatered soils. Soggy soil or standing water drown roots and dying roots invite fungi. The air pockets and air tunnels exist in TreeDiaper® because the water is kept in the watering absorbing pellets. Unlike a continuous body of water (e.g. reservoir), the gaps in between the irregular-shaped pellets allows air to go through. It helps to mitigate the root rot problem. In addition, when right sized TreeDiaper® is used, it doesn’t wet the trunk of the tree, which is the most sensitive area for root rot fungi.
Trees (and most other plants) grow roots to seek water and food. And it is one reason why mulch volcanoes (which can cause girdling roots among other bad consequences) is a problem for many trees. We have not observed any problems with TreeDiaper® and girdling roots. Here is the observations and explanations.
The depth of water in the soil varies based on soil profile. Typically the TreeDiaper® is installed on newly planted trees for a brief period of time to assist in the transplant establishment. If the correct size unit is used, the TreeDiaper® provides water to the tree roots in the root ball (as received from the nurseries) and moisture to the surrounding area which will promote growth outward to this resource. By watering the surrounding soil, no new girdling roots will be induced. It also promotes and facilitates the newly planted trees to adapt to the new environment, leading to a faster establishment.
Tree grows roots toward water AND nutrients. During extreme drought conditions, trees may grow roots only for water. Because TreeDiaper® allows deep watering, trees can get both nutrients and water in the soil.
We have never witnessed this and do not believe it would be a large issue. But most of our early field tests are in east coast and we think animals can always find better source of water. For drier part of the country (and the rest of the world), the chances are higher for a thirsty animals to chew on TreeDiaper® for water. If this happens, it has low toxicity. The animal test are: LD50 (Oral, Rat), >5000 mg/kg; LD50 (Dermal, Rabbit), >2000 mg/kg. Regarding the TreeDiaper®, it won't be too much different than being cut open by a lawn mower or weed eater, unless animals eat all the water absorbing particles. When these damages occur, simply cover with some mulch and TreeDiaper® continue does its job, but probably not at 100%!
TreeDiaper® products are not certified biodegradable. There is no biodegradable material that can meet the need for tree establishment. Newly planted trees require 2-3 years of watering to establish. However, materials have to biodegrade within 12 months to get certified as biodegradable. TreeDiaper® products made with bio-based materials will be launched in the future.
The materials used in TreeDiaper® are agricultural grade materials. The absorbent material is made of ammonium and potassium based materials. These products will become food for plants.
We have limited quantity of TreeDiaper® products made from recycled diaper materials. They are available upon special request. The majority of the products are not made from recycled materials.
When we first started the company, our goal was to recycle baby diapers. We quickly realized that nobody would buy the sanitized, cleaned and dried materials recycled from baby diapers. So TreeDiaper® products were developed to consume these materials. Currently, off shelf materials are used currently to meet the demand, while recycling baby diapers remains as a long-term goal.


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