Maintaining the right soil pH is crucial for healthy plant growth in an outdoor plant box. If your soil is too acidic or alkaline, it can hinder nutrient absorption. Here are natural ways to adjust soil pH without chemicals:

1. Test Soil pH First: Use a home testing kit or send a sample to a lab to determine your soil’s current pH level.

2. To Raise pH (Reduce Acidity):

- Add crushed eggshells or agricultural lime to slowly increase alkalinity.

- Wood ash from untreated wood can also raise pH but use sparingly.

3. To Lower pH (Increase Acidity):

- Mix in peat moss or pine needles to acidify soil over time.

- Composted coffee grounds are another effective, slow-release option.

4. Use Organic Compost: Regularly adding compost improves soil structure and buffers pH fluctuations.

5. Monitor and Retest: Adjustments take time, so retest soil every few weeks and amend as needed.

By using these natural methods, you can create an ideal growing environment for your plants while avoiding harsh chemicals. Happy gardening!