Barefoot Gardener: Bug Off! Part 2February 23, 2020, 11:19 AM HST (Updated September 8, 2020, 10:50 AM)
There are a number of different ways to control pests in your garden without the use of chemical agents. As discussed last week, the first building block is fertile, healthy soil.
After marking out a garden plot, use a shovel or sickle to remove grass or weeds in the area to be cultivated. Till the soil to a depth of 12 to 18 inches — the deeper the better. I personally created a raised bed on a terraced slope so one end is tilled about three feet deep.
After tilling, determine the pH of your soil. Clay soils are generally acidic and need a little bit of dolomite lime. Use lime very sparingly, and make sure it is of the dolomitic type. You can purchase soil pH test kits at most hardware stores or have your soil tested by the University of Hawai‘i Agricultural Extension.
Next, fertilize the soil. Start by adding lots of organic compost. For most vegetables, it’s hard to add too much compost. In one of my 15×15-foot plots, I used about one square yard of compost. Reading up on the optimum growing conditions for the veggies you intend to plant is recommended.
Manure is the next addition. Make sure the manure you choose is organic. This means that the animals that produced the manure were raised on organic feed. Preferably, the animals are free-range. If you use steer manure, make sure it is well rotted or it may burn tender plant roots. Chicken and rabbit manure are highly recommended and there is less tendency for root burn if the manure is still a bit fresh.
If you are going to grow melons or squash, add some greensand to the area of your garden planned for these rambling vines. Finally, infuse a small amount of blood meal and fish emulsion (consult the label on the products for the proper amount per square foot) and let the plot rest for about week. Then you are ready to start planting.
The best way to combat pests is not to invite them in the first place. Below is a list of companion plantings — which plants complement each other for optimal health and repelling of pests. As an aside, there is one non-botanical beetle repellant that I discovered by accident: light. Beetles are nocturnal, so if you shine solar or low voltage landscape lighting down on your vegetable or rose garden, the little buggahs won’t come near your plants.
To repel insects from most fruit and vegetable plants, intersperse the following plants throughout your garden: Asters, garlic, chives, marigolds, nasturtiums and strong herbs such as rosemary, oregano, mint and basil. For stronger, healthier greens, plant beans with your lettuce, kale, etc. Legumes fix nitrogen in the soil, which is essential for strong foliar growth. Planting beans near potatoes can also control Colorado potato beetles and conversely, potatoes control Mexican bean beetles, so both sides of the border are well patrolled.
To further protect beans, plant marigolds near them. For happy cucumbers, plant with oregano, radishes and wild marjoram. Tomatoes like to keep company with rue and dill. Plant corn with soybeans, sunflowers and white geranium. Castor beans repel most insects on vine crops (melons, squash, etc.), as does nasturtium. Careful though, as the castor plant can grow into a 15-foot high tree and has a tendency towards invasiveness.