Inside Urban Green International

Water-Saving Sub-irrigation on a Cairo Rooftop

The Solar Cities blog is about rooftop solar water heaters that are an energy efficient alternative to electric heaters. 

This photo of a Cairo, Egypt rooftop with a solar water heater included the vegetable garden benches to the right. It looks to me that the containers on the vegetable benches are watered the same way that container plants are sub-irrigated in green houses around the world. 

It is a little known fact in the consumer market that most container plants are watered by sub-irrigation using an ebb and flow system, either on benches or on a concrete floor. 

There is no narrative on the blog about the vegetable garden but the robust health of these plants leads me to believe that the containers are sub-irrigated. 

Note the plastic liners. Water collected in these basins (or added to them) will rise up by capillary action though the drain holes in the nursery pots. It is a far more efficient and water-conserving method then either hose watering or drip-irrigation. 

If sub-irrigation is a more productive, water-conserving method in the greenhouse, why aren’t we all using it for our houseplants and container vegetables? Think about it. 

Flexible Bucket Planters

You may not think of these flexible buckets as planters but they could be. The same method used here should work for these buckets. They are flexible but I believe that when filled with potting mix they will remain rigid. You do not need drainage when you use sub-irrigation (aka self-watering). 

These buckets are available in a wide range of colors. One of the brand names is Tubtrug. Their tubs are made from UV resistant, food grade plastic. They also have tubs made of recycled plastic which is not food grade. 

I also found other flexible buckets on Amazon. They appear to be widely available. 

The Biggest Little Gardens in Canada

The "Biggest Little Gardens" in New Westminster, Canada made it into the U.S. mainstream media yesterday. The Los Angles Times reported how the Fraserside Community Services organization is helping urbanites living in small spaces to grow some of their own vegetables. 

It's a great idea that can be expanded. What if these were EarthBox type sub-irrigated planters instead of simple box planters? The productivity gain would be enormous at the same time making the gardens much easier to maintain. 

This is an idea that could be copied by every religious and community service organization across the country. I plan to organize a similar program for all of the religious institutions right here in my Brooklyn neighborhood. 

In New Westminster, a Canadian city where 70% of the residents live in apartments and 25% qualify as low income, Diane Cairns had to think creatively about how to improve access to fresh fruits and vegetables. As director of the Living Well program for the community services organization Fraserside, she couldn't advocate backyard victory gardens -- not when most of the population didn't have a backyard.

There was only one solution: Bring the dirt to the people. Despite having no gardening background, Cairns designed a compact, three-tiered planter made of a handsome (and rot-resistant) cedar -- just the right size for a small balcony. The 32-inch-wide planters are narrow enough to squeeze through small apartment doors, raised high enough so no stooping is required for planting and picking, and built with a trellis on the top tier to support bean and squash vines.

The garden, soil and plants are delivered for free to whomever opts into the program. In return, participants promise to water and weed and to share leftover produce with neighbors. 

Read more...

Food Coop to Come in Spokane

This is the site of a new food cooperative that will open this fall in Spokane, Washington. A group of Brooklynites here in Bay Ridge are also in the process of forming a coop. The Main Market website is very well done and may offer some new ideas for anyone considering a coop, including my neighbors. 

This item in a Gonzaga Bulletin article caught my eye.

The co-op building will be a gold LEED (Leadership in Energy and Environmental Design)-certified project, Woods said. The building will have a full-production rooftop garden so that produce "will be plucked from the top and sold in the bottom," he said. 

Read the full article. 

This would be a good opportunity to create a sub-irrigated box, bed or bucket (or a combination) rooftop garden. Field experience demonstrates that it would be far more productive than a traditional garden watered either by hose or drip irrigation. It would also conserve water and be easier to maintain. 

A portable and versatile garden like this would be a showcase for community outreach and education. It would be of significant mutual benefit to have student involvement with the garden. 

A Visit to EarthBox Headquarters with Molly Philbin

If you are not familiar with the EarthBox this is a good explanation of how it works. Molly Philbin is the Education Director for EarthBox in Scranton, PA.

In my opinion, sub-irrigated (aka self-watering) planters should be a part of every community garden in the country. A true community garden should reach out to the entire community rather than just a small group with an interest in dirt gardening. 

While a worthy endeavor, community gardens serve only a very small percent of our urban population. Portable planters like the EarthBox are an excellent way for community gardens to reach out to the surrounding community. 

An outreach program would meet the needs of the aged, infirm and others who do not have the time or motivation to join a community garden.  

Tomato Seedlings in Pop Bottle Planters

These are some of the first heirloom tomato seedlings planted in sub-irrigated pop bottles. As you can see, I planted them deep (just up to the first leaves). 

They are growing under 40 watt fluorescent lights.  Hopefully they will develop some caliper (yet another learning opportunity). 

Stay tuned. I will post their progress. This is how they look after one week. 

Tomato Seedings Ready for Their Close-up

These are the first seedlings started March 6 and now ready for potting up into sub-irrigated pop bottle planters. They are Yellow Brandywine heirloom tomato plants. 

These seeds were propagated in a sub-irrigated planter made from recycled cookie containers (one sleeved inside the other, the outer one spray painted). I have many of these planters originally made for growing houseplants. 

The clear container leaning in the back is used as a hood when propagating the seeds. 

 

Very Little Sunshine But a Lot of Dirt From the Today Show

Visit msnbc.com for Breaking News, World News, and News about the Economy

With newspapers failing around the country, are these becoming our primary sources of information? If they are, we are in a whole lot of trouble. 

Sound bite information like this is a mirror that reflects the sorry state of our horticultural education system. We met the enemy and they are we. 

Kathie Lee Gifford: ...just sunshine and dirt...right? 

Here's some more dirt from Better Homes and Gardens about growing vegetables in containers. Over 1400 words and there's not one about self-watering or sub-irrigation...only the worn out warning about drain holes. 

Simple to Make Sub-irrigated Tote Box Planter

Update March 1, 2010: This is a later version that I would recommend. In addition to a simpler way to make the soil platform, wicking system and reservoir, it uses a fill pipe made from recycled water bottles.

Update May 21, 2009: The platform in this version is made from the cover that comes with the tote box. I used a different color lid so that you could see exactly how I cut it with a box cutter.

Most of the lids I've seen on the web were cut from the flat indented section. Note that I cut it right around the top edge of the cover.

If the tote box has a cover, this is how I would make the platform. I like it better than any of the other platform materials...and it's free. 

The two objectives in designing this homemade sub-irrigated (aka self-watering) planter are ease of construction and low cost. I believe both objectives are met with this design. All you need is a pair of scissors and a tool to poke holes. You do not need DIY power tools and you could make it from recycled materials.

Essentially the same construction method for making this bucket planter insert was used to make this box planter with one significant difference. The larger area of the box platform needs support. The upside down deli containers do that. They could be any plastic containers such as yoghurt containers. You could also use aluminum soda cans. Recycling is good!

You could make the platform from window screen material (recycled if available) instead of the vinyl tiles. If additional support is needed, duct tape the edges of the platform to the sides of the container.

You can see that you can vary the height of the reservoir depending on the height of the recycled containers you use. You may also prefer to add one or two more soil wicks. These are decisions that are relative to your climate and water consumption.

This planter was made from a plastic tote box but the same method can be used to make a wooden box planter. All you need do is line the wood box with sheet plastic (called visqueen in the horticultural trade) before installing the wicking containers and platform.

There is no proprietary secret about how these sub-irrigated planters work. They all use a simple principle of physics called capillary action. It is a highly accurate and consistent method of irrigation. It is far more beneficial for plants than gravity fed top watering.

You can see capillary action at work as water rises in an ordinary household sponge or paper towel. An even better way to learn about it is to grow some plants in recycled pop bottle planters. The planters are clear and you can see it all happen as the plants grow.

In this design, the soil (potting mix) in the two corner deli containers acts like a sponge. The containers of potting mix wick the water in the reservoir up into the growing area of the planter. It’s that simple. Just remember to use potting mix, not soil mix and for sure do not use soil from the ground (dirt)

One very important factor to remember is that unlike animals plants have no brain. They do not have the ability to drink or not drink as an animal pet does.

There are many claims that you cannot over water plants in these sub-irrigated boxes. That is a factual mis-statement but is functionally true when growing vegetables in sunlight. The rate of photosynthesis is such that water is consumed at a very high rate making it very unlikely that you will over water.

Move the planter into low light or indoors and you will most definitely over water the plants if you constantly top off the reservoir. The plant will die from a lack of oxygen in the soil. It will drown.

This topping off practice encouraged by the erroneous term “self-watering” is why these planters have a less than positive reputation in the houseplant community. It isn’t the fault of the planter. It’s a problem of operator error due to widely published misinformation.

The best practice when using sub-irrigated planters is to test the soil moisture not just check the reservoir level. Do not rely on the widely recommended finger probe. It is tricky to learn and highly subject to error.

Use a soil probe to pull a sample from the bottom of the planter and squeeze it between your thumb and forefinger. Use this method and you will soon learn to discern various levels of soil moisture with a high degree of accuracy.

The key words of irrigation are consistency and even distribution of water throughout the soil and root system. Use sub-irrigation in adequate light and your plants will thrive.

Simple Sub-irrigation Insert

You can make this sub-irrigated (aka self-watering) bucket planter with a pair of scissors or snips. This reservoir/wicking insert is about a simple as you can make. It will work in any watertight container. 

Most of the plans for self-watering bucket planters on the web use two buckets, one sleeved inside the other to create the reservoir. This also requires a power drill and hole saw. Even if you use free recycled buckets, why waste them if you don't have to?

Other than cutting the platform with scissors or snips, the only other fabrication is to poke holes in both the platform and the deli container (soil wick). I used a metal skewer heated on the stove. Of course, you could also use a Dremel rotary tool if you have one.