Tropical Gardening Helpline: Gardening tips for times of drought

  • Mulching around your plants can help retain moisture and discourage weed growth. (Photo courtesy /
  • Catching rainwater or recycling household water can help reduce your water use. (Photo courtesy /

Kris asks: I am surprised at the number of weeks we have gone without rain. What advice can you offer to gardeners in the middle of this long dry spell?

Tropical Gardener answer: Even though we have had some rain in the past week, it is not really enough to mitigate the drought conditions we are living through this year in Kona. Below find a few gardening suggestions for dry times in Kona.


First, whether you call it climate change, climate confusion or global warming, scientists pretty much agree that we can expect more weather extremes which will likely bring hotter, drier weather and some severe storms our way. When we have extreme rain storms that come down hard and fast, it can result in floods and landslides instead of replenishing our water table. Wind extremes make dry conditions worse and are hard on the plants in our gardens. The lack of rain we are experiencing now is likely to continue for a while. With long lasting drought conditions seemingly imminent, we may want to take some immediate water saving steps while we plan ways to keep our plants growing in the dry times ahead.

Many plants, especially drought tolerant varieties, can accommodate long dry periods with judicious watering. By watering deeply, you can get the plant’s roots to grow deeper so they can find moisture when the top layers of soil dry out. You can also change irrigation systems to water longer and less frequently to achieve this goal. For plants that are established or not on an irrigation system, some hand watering might be in order if they seem stressed. Give them a long drink (10 to 15 minutes) weekly. Water the soil directly for the most efficient water use. Avoid losing water to mid-day evaporation by watering early in the morning or late in the afternoon. Installing drip irrigation where possible can also help insure that water is used most efficiently.

Adding organic matter to your garden either by working it in or spreading it on top of the soil will help hold moisture near you plants. A few inches of mulch placed a few inches from the trunk of the plant can reduce water evaporation while discouraging thirsty weeds and encouraging the microorganisms that support healthy soil. A combination of newspaper and mulch can work well. Avoid fertilizing during these dry times. The production of new growth increases water needs.

For longer term solutions to gardening with less water, consider planting native plants as well as drought tolerant species. A locally produced book, Plants for the Tropical Xeriscape: A Gardener’s Guide by Fred D. Rauch and Paul Weissich can be very helpful in selecting plants. You might also want to check out websites with lists of drought tolerant vegetables. This is a good one:—consider-these-heat-drought-tolerant-vegetables-f7d7816f372.

Another long-term solution for combating drought conditions is to set up catchment systems to catch water off your roof when it does rain. Rain water contains lots of nutrients that get filtered out of city-supplied water. It’s good for plants, though needs to be filtered for drinking. Gray water that was used for boiling vegetables, bathing or washing dishes or clothes is OK for non-edible plants as long the soap or other products in the water are biodegradable and won’t harm your plants.

The time is right to start integrating water saving plants and systems into your garden or landscape. For more ideas go to a UH Master Gardener publication at Do keep growing but keep water economy in mind.

Email plant questions to for answers by Certified Master Gardeners. Some questions will be chosen for inclusion in this column.

Diana Duff is a plant adviser, educator and consultant living in a dryland forest north of Kailua-Kona.

Gardening Events

Monday: “Irrigation Water Treatment Workshop for Farmers” from 4-6 p.m. at the UH Komohana Center in Hilo at 875 Komohana Street in Room D-202. Demonstrating water treatment systems to comply with food safety requirements with Sharon Wages and Jenson Uyeda from UH. Free event. Go to to register.

Saturday: “Work Day at Amy Greenwell Garden” from 9 a.m. to 12:30 p.m. Meet at the Garden Visitor Center across from the Manago Hotel in Captain Cook. Volunteers will be able to help with garden maintenance and are invited to bring a brown bag lunch. Water and snacks provided. Call Peter at 323-3318 for more information.

Farmer Direct Markets

Wednesday: “Hooulu Farmers Market” 9 a.m. to 2 p.m. at Sheraton Kona Resort &Spa at Keauhou Bay

Saturday: “Keauhou Farmers Market” 8 a.m. to noon at Keauhou Shopping Center

“Kamuela Farmer’s Market” from 7 a.m. to noon at Pukalani Stables

“Waimea Town Market” from 7:30 a.m. to noon at the Parker School in central Waimea

“Waimea Homestead Farmers Market” from 7 a.m. to noon next to Thelma Parker Gym in front of Thelma Parker Library.

Sunday: “Pure Kona Green Market” 9 a.m. to 2 p.m. at Amy Greenwell Garden in Captain Cook

“Hamakua Harvest” 9 a.m. to 2 p.m. at Highway 19 and Mamane Street in Honokaa

Plant Advice Lines



Tuesdays and Thursdays: 9 a.m. to noon at UH-CES in Kainaliu – 322-4893

Mondays and Fridays: 9 a.m. to noon at UH CES at Komohana in Hilo 981-5199 or

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