Sissoo spinach and basil in our Costa Rican courtyard
Lynette and I grow vegetables, fruits and culinary and medicinal plants in Vermont April-Nov and in Costa Rica Dec-March. What we like to grow most differs in each place, for sure. Our favorite plants to grow in Vermont include lilies, peonies, black raspberries, hardy kiwi, tomatoes, peppers, spinach plus dozens of types of coleus and plectranthus in pots.
And in Costa Rica our favorite garden plants are bougainvilleas (in a rainbow of colors), tomatoes (but they are tough with weather and iguana challenges), perennial peppers, coconuts, 6 types of citrus, lemon grass, flor de Jamica (for bright red, tart-flavorful medicinal tea), quelite greens (bush variety) plus basil and Sissoo spinach in pots.
To reduce work, save water and boost soil fertility we have developed various intensive growing methods. Five of these techniques work well in both Vermont zone 4-5 and tropical Costa Rica, with some climate-specific variations.
Vetiver plants mulched with their own trimmings
Intensive beds (with mulch)
I began gardening 40 years ago in a ¼ acre plot using a Troy-Bilt rototiller. I discovered that tilling my garden soil multiple times every year depleted soil health through excessive aeration, plus killed earth worms and reduced water retention capacity of the soil. I also discovered I could grow the same amount of food in much less space by planting more intensively. How? I was guided by Ruth Stouts thinking from 50 years ago: building raised beds and mulching them to the max with all sorts of VT organic matter: spring weeds, summer lawn clipping, fall leaves, and composted vegetable waste all year. By using mulch and organic waste to build soil fertility I am able to plant plants closer together and use much less water (and no fertilizer).
But mulching in the tropics is more challenging. Organic matter breaks down much more quickly. So we discovered some tropical solutions. The best overall solution is to use abundant organic waste produced during the June-Nov rainy season to make compost and add it to growing beds Dec-March. But the best specific innovation we discovered was vetiver grass. It grows 3 ft tall in the wet season and the roots go 2-3 times deeper than that helping to stop soil erosion and improve soil quality. Then you can harvest the grass in Dec-Jan and the trimmings make a superb mulch that breaks down slowly during the dry season, retaining moisture and adding organic matter for the growing season.
10 month old white yam weighing 15 pounds
Training vining vegetables and flowers to grow vertically let’s you increase your yield per square foot because you can fit more plants into the garden. But saving space and increasing yield is only one reason to make trellises to grow vining tomatoes, peas, cucumbers, pole beans, squash and melons. Other benefits include easier harvesting, less bending and strain, easier weeding and pest control, and growing decorative green “walls”.
Our favorite vining plants in Vermont are cucumbers and perennial hardy kiwis; we provide trellises to hold them. In Costa Rica we plant a tuber locally called Ñame and also known as White Yam, Winged Yam and botanically Dioscorea alata. We plant at the base of a tree, the vibe can grow 30 ft high and the tuber can take almost a year to mature, weighing as much as 20-30 pounds. We eat them like potatoes, but there are other varieties of this vine that are invasive and poisonous (causing problems now in Florida.
Lynette adding coir to rice bags on drip irrigation
Pots (self watering!)
The key to growing in pots is to have enough, but not too much, water. This can be achieved with self-watering features or drip irrigation, as well as using the right kind of water-retaining soil mixes. In temperate climates like the US peat-based soils are used to absorb, retain and release water as plants require it. But peat is hard to get in Central America. So, in Costa Rica we use the waste material from the outer husks of coconuts, called “coir”.
We grow market vegetables in Costa Rica (tomatoes, eggplants, cabbage) using recycled rice bags filled with coir and compost and watered with drip irrigation.
Lady finger bananas ready to harvest
Our hardy kiwi in Vermont require protection from north winds so we created a micro climate for our perennial fruit and berry garden using our house as the wind break on one side and evergreens on the other. The garden area then opens to full southern exposure creating a micro-climate offering an advantage of 1-2 growing zones.
In Costa Rica, the strong easterly Papagayo winds in the Guanacaste region knock down banana trees so we plant them on a shielded west slope of our house. We also use water-catching sunked beds to grow the best mini bananas. You will rarely find in US stores these sweet but tangy US Lady Fingers from India.
Hugelkultur makes sense.
Hugelkultur may be the best organic waste management and soil building technique for perennial gardening you probably never heard of: http://www.willraap.org/2014/09/02/hugelkultur-how-to-build-rich-soil-using-all-your-yard-waste/
PLUS, Gravitropism: possible innovation for intensive gardening?
After evolving from the ocean hundreds of millions of year ago plant stems had to learn to grow up for photosynthesis and down to capture nutrients with their roots. Gravitropism (also known as geotropism) is plant growth in response to gravity. Upward growth of stems and leaves, against gravity, is called "negative gravitropism", and downward growth of roots is called "positive gravitropism". NASA and space agencies in other countries are exploring how zero gravity or variable gravity affects growth, and how to use gravitropism to optimize plant performance. Gardener’s Supply is testing new container gardening systems that boosts plant yields using variable gravity. Keep your eyes open for our test results.