Honolulu Star-Advertiser

Wednesday, April 24, 2024 79° Today's Paper


Column: Expert offers some tips to start an urban garden

A recent column I did on agroforestry spawned a number of reader inquiries about urban gardening. To get the skinny on getting started, I spoke to Nat Bletter, co-founder of Madre Chocolate and NattybyNature.net. He has 22 years of experience in botany, documenting exotic fruits and vegetables throughout the world. With a Ph.D. in ethnobotany, he has created the ultimate urban garden in his Palolo backyard.

Question: How do I plan my garden?

Answer: Think about the intersection of what you like to eat and what grows easily in your Hawaii climate. Look around your neighborhood and see what grows well, and talk to your neighbors who might even be willing to give you cuttings or seeds of their successful plants.

Q: Is grafting a strategy?

A: There are a myriad of reasons to select a grafted tree over a seedling:

>> You get flowers and fruit in one to two years versus five to 15 years on a seedling.

>> The fruit will be true to the parent of a known good variety and not a gamble with a seedling that might be thorny, bitterand nonproductive.

>> You can have multiple varieties grafted onto one tree so, for example, you can spread out the season to have early summer, late summer and winter avocados all on one tree.

>> You can squeeze in many varieties to a small space, like the 64 trees with 113 (grafted) varieties in my one-sixteenth of an acre.

Q: What about rain, light and wind?

A: Keep these in mind, especially as they vary across your garden, since some plants, like chilies, like full sun and drier conditions, and others like coffee and cacao can handle more shade and like more water and less wind.

Q: What about size of the plant in relation to your yard?

A: You should space trees a minimum of 8 feet apart, but you can put low herbs and veggies in between those as long as the herbs aren’t overgrowing the trunks.

Q: How do you build up the soil?

A: Maintain soil with composting, worm bins, nitrogen fixing plants, hugelkultur (a German mound culture technique) and mulching with wood chips or even cardboard boxes (with plastic tape removed). Mulching helps build up organic matter in the soil and keeps water from evaporating from the soil quickly, lowering your watering bills.

Q: Should I plant nitrogen fixing plants?

A: Yes, you should. Nitrogen fixing plants, like legumes, add valuable nutrients to the soil. Legumes such as pigeon pea, butterfly pea, wing bean, lima bean, monkey pod, rainbow shower, koa, Hong Kong orchid tree and ice cream bean make great nitrogen fixers. If you have haole koa, “chop and drop” their leaves and branches to use them as mulch around other plants; just remove all seed pods first.

Q: What about fertilizer?

A: Apply at least quarterly or more with heavy feeders like chilies. I like to use both soil fertilizer and foliar (leaf) fertilizer that is sprayed on the underside of the leaves. For soil fertilizer, you can use a commercial fertilizer, local zoo doo from the Honolulu Zoo, homemade compost or a worm bin.

Q: Do I need an irrigation system?

A: Keeping plants well watered, especially in Hawaii’s hot — often dry —summers, is key to the plants’ survival. When you’re first starting, you can just water by hand with a garden hose with a good long-distance spray nozzle head so you can get a better idea of the time involved and your plants’ needs. If the time invested in keeping the soil moist to the touch becomes too much, you can install a relatively low-cost timer system with drip irrigation.

Q: Where do I get seeds? Plants?

A: There are free stores all over Oahu. See (nomoola.com/stores), 808 greenthumb on FB. Nurseries include Frankie’s Nursery, Ko‘olau Farmers, Madre Chocolate.com (for chilis), Project Lemon Tree, PlantIt­Hawaii, @voo.dooplants on IG, Sharon’s Plants, Lowe’s and Home Depot garden centers. I suggest you support local nurseries, which know the local plants better.


Rob Kay, a Honolulu-based writer, covers technology and sustainability for Tech View and is the creator of fijiguide.com. He can be reached at Robertfredkay@gmail.com.


By participating in online discussions you acknowledge that you have agreed to the Terms of Service. An insightful discussion of ideas and viewpoints is encouraged, but comments must be civil and in good taste, with no personal attacks. If your comments are inappropriate, you may be banned from posting. Report comments if you believe they do not follow our guidelines. Having trouble with comments? Learn more here.