Note the fallen leaves. The all-annuals pollinator garden will soon be history. How sad but Spring will be here before we know it. Next year the garden will be grown from seeds sown in indoor light gardens instead of annual starter plants from garden centers. My STEM-based urban greenscaping lab is now back in business after a long summer recess while crossing the country.
No Drips Allowed!
Other than a small amount of water that exits from the overflow drain, there is no hazard of water dripping on the neighbor below when you grow in SIPs. Dripping water, however, is a very common problem with traditional drench and drain pots on balconies.
Dripping water is the cause of many disputes in balcony buildings. Count the ways that drain hole planters are a dumb idea regardless of what your local garden column writer, favorite gardening book author or "master gardener" advises. Clay pots are from the time of outhouses before indoor bathrooms. They have no functional benefit. Planters with drain holes are counter productive in an age of drought and the need for sustainability.
My goal for this SIP balcony garden is "no drips." Human error is the only way for it to happen. If too much water is added too quickly to the water & oxygen reservoir system the result can be a "drip error." I don't' want to be the drip who did it. Here is how the reservoir system works in actual practice, particularly in elongated window box type of SIPs.
In this design the fill pipe is in one corner and the overflow drain on the diagonally opposite corner. This arrangement is to ensure the filling of all the reservoir segments and to ensure absolutely even soil moisture distribution.
When you add water it takes some time for it to saturate the soil and fill the reservoir nearest to the fill pipe before it travels to the opposite end where the overflow drain is located. The added water is filling the reservoirs and saturating the soil sequentially from one end to the other.
It is easy to become impatient and have too heavy a hand when adding water. The result is a strong surge of water that can cause a drip problem. To remedy this pay attention to what you are doing and add a catch basin below the overflow drain.
I made several overflow drains from Glad type 24 oz (rectangular) food containers. I cut them down to fit under the overflow drains. As further insurance i added a piece of good quality duct tape to attach them to the planter under the hole. They can be easily removed without damaging the duct tape and installed on the next planter to fill. You can get a better look at the temporary catch basin (lower right) by clicking on the photo for an enlarged view.
Be Sure to Tamp the Soil Down Firmly to Create a Good Soil Wicking System
I haven't had a problem with any of the 16 SIPs on the balcony. They are all working very well, saving water, time and growing plants that are pretty spectacular. I have, however, realized that I have not emphasized the need to tamp down the soil between the reservoirs enough. Doing this removes the possibility of air pockets in the wick system.
Push the soil mix down firmly between the reservoirs with your fingers. Use a piece of 1/2" wooden dowel to save your fingernails if necessary. You don't need a hammer but push firmly. No patty-cake, patty-cake with palms.