Garden Myth Buster: Common Gardening Advice, Tested for California

A bag of lime, a jar of coffee grounds, a layer of gravel in a pot: garden advice often arrives as one small job that promises to fix a problem. Before adding it to the weekend list, ask what it is meant to change and whether your garden needs that change.

This collection helps you work through those decisions. It draws on UC Agriculture and Natural Resources and UC Statewide IPM, with attention to the plants, soils and growing conditions in California. A useful recommendation for one site can be a poor fit for another, even a few miles away in Santa Cruz County.

Start with the question that matches the job in front of you. If you are filling a container, read about rocks and drainage. If the irrigation timer is still on last season's program, start with watering. If a soil amendment is on your shopping list, find out what a test can tell you before buying it.

The point is to keep the useful part of a tip and recognize its limits. Some advice needs a small adjustment; some solves a problem you don't have. The linked sources let you look beyond a verdict and see what the recommendation depends on.

Soil, Compost, and Fertility

Soil changes are easier to plan when you know what you are starting with. These guides cover testing, amendments, compost and the work a bed actually needs.

• Can Hardpan Soil in California Be Fixed?
• Can You Compost Citrus Peels? Piles and Worm Bins
• Do Pine Needles Make Soil Too Acidic for Plants?
• Do Rocks in Pots Improve Drainage?
• Do You Need Expensive Soil to Start a Garden?
• Do You Need a Compost Tumbler to Make Compost?
• Do You Need to Add Lime to California Garden Soil?
• Do You Need to Till Your Soil Every Spring?
• Does Adding Sand to Clay Soil Improve Drainage?
• Does More Fertilizer Mean More Fruit?
• Does Potting Soil Last Forever?
• Is Compost Tea Really Better Than Compost?

Kitchen Scraps and Home Remedies

The kitchen offers plenty of compost ingredients. That does not make every scrap a fertilizer dose or every household product suitable for a plant.

• Are Banana Peels a Good Garden Fertilizer?
• Do Coffee Grounds Make Soil Acidic?
• Do Eggshells Add Calcium to Soil Quickly?
• Do Eggshells Reliably Deter Slugs?
• Do Rusty Nails Help Plants Grow?
• Does Epsom Salt Help All Plants Grow Better?
• Does Sugar Water Help Transplant Shock?
• Is Dish Soap Safe to Spray on Garden Plants?
• Is Vinegar a Safe and Effective Weed Killer?

Watering and Irrigation

Compare the plant, soil and equipment before deciding how often to water. A container and an established landscape rarely need the same routine.

• Do Drought-Tolerant Plants Need Zero Water?
• Does Deep Watering Mean Soaking for Hours?
• Does Drip Irrigation Waste Water?
• Does Watering in the Sun Burn Plant Leaves?
• Should You Water Your Garden Every Day in Summer?
• Should You Water Your Lawn Every Day in Summer?

Pests, Pollinators, and Sprays

Identify the visitor and the damage before choosing a response. These articles consider control methods, beneficial insects and the care needed with pesticides.

• Are All Butterflies and Moths Good for Gardens?
• Are Beer Traps Really the Best Slug Control?
• Are Organic Pesticides Always Safe to Use?
• Do All Bees Sting? Why Your Garden Needs Them
• Do Compost Bins Really Attract Rats?
• Do Marigolds Actually Repel Garden Pests?
• Does Mulch Really Attract Termites to Your Home?
• Does Planting Garlic Around Roses Stop Aphids?
• Is Neem Oil Safe to Spray on All Garden Plants?
• Will Bought Ladybugs Stay in Your Garden?

Timing, Technique, and Garden Chores

Review the purpose of a chore before repeating it. Timing, plant type and the size of the garden all affect the decision.

• Do You Have to Start Seeds Indoors for a Good Harvest?
• Do You Need to Rotate Crops in a Home Garden?
• Does Companion Planting Always Work as Described?
• Does Planting by Moon Phases Improve Yields?
• Does Pulling Weeds Make More Weeds Grow?
• Is Fall Too Late to Plant in California?
• Should You Prune All Fruit Trees Into a Vase Shape?
• Should You Remove All Fallen Leaves From Your Garden?
• Should You Use Wound Paste on Pruning Cuts?

What You Can and Cannot Grow Here

A small yard, shade or a coastal location sets conditions to work with. Use these guides to choose plants and expectations that fit.

• Can You Grow Blueberries in California?
• Can You Grow a Productive Garden in Shade?
• Do California Native Gardens Look Messy and Brown?
• Do Heirloom Tomatoes Really Taste Better Than Hybrids?
• Do Succulents Really Need Zero Maintenance?
• Do You Need a Big Yard to Grow Your Own Food?

Frequently asked questions

Do coffee grounds acidify garden soil?

Do not rely on used grounds to set soil pH. UC Sonoma's garden-remedy guidance recommends them as a compost ingredient rather than an acidifying treatment. If pH is a concern, test the soil and choose any correction for the intended plant. Read the coffee-ground guide above for more detail.

Should I put a gravel layer in the bottom of a container?

No. UC's explanation of container drainage describes how a coarse layer can hold water in the finer potting mix above it. Use appropriate potting mix and keep drainage holes open. A gravel layer is different from a small piece of mesh used to retain mix without blocking a hole.

Do eggshells stop slugs and snails?

They are not a dependable barrier. UC IPM reports that crushed shells have not been shown to deter these pests. Confirm what is feeding on the plants, reduce suitable hiding places around vulnerable crops, and consider the control methods in the full guide. If using a bait, follow its exact label and protect children, pets and nontarget wildlife.

Is fall too late to plant in California?

It depends on the plant and site. Fall can be a useful establishment window for many California natives, with cooler weather and the prospect of winter rain. UC's fall-native-planting guide emphasizes matching the plant to its growing conditions. Check soil moisture, drainage and watering needs rather than assuming rain will arrive on schedule. Vegetable planting has its own crop-specific timing.

Is organic automatically safe?

No. A pesticide's suitability depends on the product, intended use and label directions. UC IPM's guidance begins with identifying the problem and considering nonchemical options. Follow all restrictions, including those protecting pollinators. An evening application does not automatically remove risk from residues or make every product appropriate.

Tools that go with these guides

After you have chosen a next step, use the planting calendar to explore crop timing and garden conditions for local planning context. Keep a note of what you changed and what happened. That is more useful next season than a longer list of rules to follow.