Now a little over one year into our Intrepid Gardens experiments, we are re-assessing and implementing new designs before the monsoons in May.
Before we get into the to-do’s, we have to be honest about what worked and what failed.
The poly bag towers were complete failures on the scorching roof garden. This was obviously a disappointment after seeing great results in temperate climates, but we are, after all, in the tropics. We must use what works here. As we mentioned in August, the bags held up for a season but required constant watering. The woven sides allowed the soil to breathe, but also for huge water losses through evaporation. The peppers, tomatoes, and eggplant saw very poor yields because of this.
The wooden egg crates sourced from local shops served slightly better, but in the end the monsoons were too much for the light-weight wood. As you can see at right, the ends collapsed and the crates are collecting stones and weeds until we can transfer the soil into new systems.
While our water-conservation efforts did not fail completely, they definitely need to be increased for the extreme environment.
The successes included a relatively large crop of chillies. We only planted three bushes, but we harvested enough for cooking, drying, and pickling. The passion fruit vine is also doing well and beginning to climb on our new arbor, constructed of recycled pipe and lumber seconds from just down the road, which is also covered with a 30% shade cloth to shield the more tender varieties in the late afternoon.
Of our three fruit trees, the cherry failed but the lemon and varigated orange are going strong. The only pests they have seen are the new caterpillars. We don’t find this all bad if it means more beneficial insects are moving in. We simply pick off the caterpillars and transfer them to the wild area next door.
We have also seen a great up-tick in lizards and birds. More geckos and even large lizards are now living on the roof behind pots and hanging baskets to control the pests drawn to our veggies, and small groups of birds visit daily to clean up black soldier fly grubs in the courtyard compost.
In the courtyard we have also begun pulling up pavers to increase the habitat space with native shrubs and legumes, which will help build soil in the rooftop systems. Along the walls we have added 11 new edible varieties, 8 of which are perennial. We’ll be sure to update you on how they do in the semi-shade environment.
Water conservation is our main focus on the roof. We have already begun to plant out a few large terracotta pots to replace the poly grain sacks. While we would prefer to be recycling, the pots are made of local clay and keep the plant roots much cooler. In our recycled plastic bucket we are testing the use of burried clay water jugs for irrigation. As you can see to the right. The soil in line with the broad base of the jug is much darker than the soil covering the neck of the jug. As soil and roots dry out they create a natural suction to draw more water through the unglazed, porous clay. This is an ancient irrigation technique used in multiple parts of the world, including rural homesteads in Sri Lanka. The local seal of approval is good enough for me, but if you would like more data on their efficacy check out this report which also outlines how to implement them in a home garden. Our next step here will be to mulch the soil and plant it out.
We also plan to construct 2 towers to increase our vegetable growing space, as well as planters to sit on top of the half wall around the slab to create privacy and provide more flowers for pollinators. This section will include perennial native flowers as well as some cucumbers and other vine crops to train up trellises between the cement posts.
Composting is an on-going and integral part of any sustainable food system, so we are planning to beef-up our operations in the coming months. We have already added a new pile in the courtyard and will be expanding from one small bin on the roof. We will also be detailing the methods and applications for compost teas in the coming weeks.
Finally, we are undertaking a major expansion to the whole project by partnering with friends to establish a home-scale permaculture site closer to the heart of Colombo. The garden will be a cooperative effort to supply both households with more staple crops (potatoes, beans, etc.) as well as wildlife habitats and an educational model for the public. The home serves as a kind of community center for weekly visitors with whom we are excited to share the process. We will also be tracking the progress and detailing the design of that site for you here.