Here are some tips and hints for working in the garden. You can incorporate all your used tea to help maintain the pH in soil

For Flowers:

Sprinkle new or used tea leaves (from loose or tea bags) around your rosebushes and cover with mulch to give them a midsummer boost. When you water the plants, the nutrients from the tea will be released into the soil, spurring growth. Roses love the tannic acid that occurs naturally in tea.

Feed your ferns

Schedule an occasional teatime for your ferns and other acid-loving houseplants. Substitute brewed tea when watering the plants. Or work wet tea leaves into the soil around the plants to give them a lush, luxuriant look. Use a lukewarm tea, one that is brewed delicately–not too strong. Perfect for re-brewed tea.

Prepare planter for potting

For healthier potted plants, place a few used tea bags on top of the drainage layer at the bottom of the planter before potting. The tea bags will retain water and leach nutrients to the soil.

Enhance your compost pile

To speed up the decomposition process and enrich your compost, pour a few cups of strongly brewed tea into the heap. The liquid tea will hasten decomposition and draw acid-producing bacteria, creating desirable acid-rich compost. Black tea is best.

Sources: various