Tropical Gardening Helpline: Get your garden ready

  • Cover cropping is a standard practice for farmers and gardeners who want to create green manure to incorporate into the soil. ( Diana Duff)

  • Leguminous plants produce pods and fix nitrogen in the soil. ( Diana Duff)

  • Sunn hemp, or crotalaria, is an excellent tropical legume to grow for green manure and nitrogen fixing. ( Diana Duff)

Ken asks: I want to prepare my garden space now for planting vegetables in a few months. How do you recommend I best do that?

Tropical Gardener Answer: You are a smart gardener to realize that preparing the ground for your vegetable garden well in advance makes success more likely.


Hopefully you have purchased or ordered seeds so that you know what you will be planting. Free seeds are available to folks who are willing to become members of the Community Seed Library at the Kailua-Kona library. Johnny’s and Baker’s Creek have online seed catalogs with lots of interesting choices. Many of their seeds are organic and, if you avoid hybrids, you can save the seeds for the next round.

Most vegetables prefer a slightly acid soil at about pH 6.5. You can buy basic test kits at a hardware or gardening supply store to figure out if you have plant friendly soil. If you want to buy soil for raised beds, check with Deano at Organic Matters and see what he’s got available that might work for you.

Soil in Kona is often slightly alkaline. To acidify your soil, add organic matter like compost or manure that are well broken down. These will work slowly. A quicker trick to lowering pH is applying elemental sulfur. Check the label for proper application. It may take several months and two applications to significantly lower the soil’s pH, but it will help. To raise your soil’s pH apply a liming agent.

Adding organic matter not only helps to lower pH but it also helps retain moisture and encourages microbial activity while improving soil structure. If you have a few months before planting, you can also grow your own organic matter. Consider growing a leguminous cover crop that sequesters nitrogen from the atmosphere into your soil. Sunn hemp, perennial peanut or any bean will do the job. Lots of information exists online about the use of these cover crops. Chopping and incorporating them in your garden will definitely enhance soil health.

It will help your plants =if you remove any large rocks that might interfere with growth. You also want your soil to be friable, loose and to drain well. If your soil has not been worked lately do so to prepare it. This will also activate any dormant weed seeds, giving you a chance to reduce the weed population before you plant. When you are working the soil, is a good time to add organic matter, compost and other amendments

Green sand is a good amendment to consider. It is a good source of many plant nutrients and helps improve the soil structure.

You can get seedlings started in small pots or trays about a month before planting out. Though soil improvement can take a while, working on that in next few months will definitely help you move toward the goal of healthy soil that will support healthy plants. Happy growing.

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 part time in Kailua-Kona.

Gardening Events

This week:

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: “Ho’oulu 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 7:30 a.m. to 1 p.m. 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. – 2 p.m. at Amy Greenwell Garden in Captain Cook

“Hamakua Harvest” 9 a.m. to 2 p.m. at Hwy 19 and Mamane Street in Honoka’a

Plant Advice Lines


Anytime: Tuesdays &Thursdays: 9 a.m. to noon at UH-CES in Kainaliu – 322-4892

Mon., Tues. &Fri: 9 a.m. to noon at UH CES at Komohana in Hilo 981-5199 or

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