Your August Garden Checklist for Santa Cruz County
August is when Santa Cruz gardens live a double life. The summer harvest is still pouring in, but smart gardeners are already planting for fall and winter. This is often the warmest month of the year in our county, with inland valleys reaching the mid-90s and even coastal areas seeing occasional heat spikes into the 80s. UC ANR's California Garden Web notes that August plantings of cool-season crops are essential for a productive winter garden in our mild climate.
What to Plant in August
Fall planting begins in earnest. Direct-sow lettuce (Winter Density, Rouge d'Hiver), arugula, spinach (Bloomsdale, Corvair), and radishes in afternoon shade or under 30% shade cloth. Seeds germinate poorly in hot soil, so water seed beds twice daily and cover with a thin layer of burlap until sprouts appear.
Transplant broccoli, cauliflower, cabbage, and kale seedlings into the garden. Set out Brussels sprouts transplants no later than mid-August for a December harvest. These are slow growers and need every available day.
Plant fall peas (Cascadia, Sugar Ann) along the coast and in mountain areas. Inland valley growers should wait until September when temperatures moderate. Sow a final succession of cilantro and dill.
This is also garlic planning month. Order seed garlic now from a reputable California source for October planting. Popular varieties for our area include California Early, California Late, and Inchelium Red.
What to Harvest in August
Tomatoes are at their absolute peak. Dry-farmed tomatoes (a tradition in parts of the Pajaro Valley) develop intense, concentrated flavor this month. Sauce tomatoes like San Marzano and Roma are ready for canning and preserving in quantity.
Corn is ready when the silks are brown and dry and a pressed kernel releases milky (not clear) liquid. Pick and eat the same day for peak sweetness. Peppers, eggplant, and summer squash continue producing. Melons are ripe when the stem slips easily from the fruit with gentle pressure.
Figs (Mission, Kadota, Brown Turkey) produce their main crop this month. Pick when fruit is soft, drooping on the stem, and shows a small drop of nectar at the base.
Winter squash and pumpkins are sizing up. Do not harvest yet. Let them continue to develop sugars and a hard rind.
What to Maintain and Protect
Water is everything this month. Monitor plants daily for signs of water stress: wilting in early morning (not just afternoon heat wilt), curling leaves, and dropping flowers. Increase irrigation frequency during heat waves. A well-mulched garden needs significantly less water than bare soil.
Clean up spent crops promptly. Pull bolted lettuce, exhausted bean plants, and any crop that has finished producing. Compost healthy plant material and dispose of anything with disease symptoms in the trash.
Start building compost piles with the abundant garden waste. Layer green material (spent plants, kitchen scraps) with brown material (dried leaves, straw, cardboard) at a roughly 1:3 ratio. UC Master Gardeners recommend turning the pile weekly and keeping it as moist as a wrung-out sponge.
Deadhead annual flowers to keep them blooming through fall.
What to Watch Out For
Tomato spotted wilt virus (TSWV) shows up as bronzed, ring-spotted leaves and distorted fruit on tomatoes and peppers. It is spread by western flower thrips. There is no cure; remove and destroy affected plants. UC IPM recommends removing weeds around the garden that harbor thrips.
Corn earworms tunnel into the tips of corn ears. Apply a drop of mineral oil to each ear's silk channel after silks begin to brown. This smothers eggs without chemicals.
Whitefly populations peak in August. Yellow sticky traps help monitor numbers. If populations are high, UC IPM suggests reflective mulch (silver-colored plastic) around tomato plants, which disorients whiteflies.
Birds and squirrels target ripening tomatoes and figs. Bird netting over fruit trees and individual tomato cages is the most reliable protection.
This month: Get your fall brassica transplants in the ground by August 15. Every week you delay costs you weeks of harvest on the other end.
For more help with fall planting, check out our free California Fall Garden Planting Guide at Your Garden Toolkit.
