Are Coffee Grounds The Secret To Thriving Poinsettia Plants All Winter Long?

There are some genius ways to reuse old coffee grounds in your home and garden, including using them as fertilizer. Some plants seem to enjoy their morning cup of joe, while others are less than thrilled. As the holiday season approaches and you start setting out poinsettias (Euphorbia pulcherrima), you may be wondering how to care for a wilting poinsettia plant. Would some coffee grounds help it perk back up, or is there a better solution?

Well, it's a mixed bag. Coffee grounds can be used as a fertilizer for some plants, but they aren't a super food. They contain nitrogen, phosphorus, potassium, calcium, and a few other nutrients, and they can even improve the soil's overall texture and quality. However, the amount of each nutrient is relatively low. While the soil texture benefit can be helpful, especially in the garden, most potting soil already has additives to achieve these benefits. If your poinsettia is potted, the soil is likely just fine without coffee grounds.

However, there's another reason that coffee grounds aren't really a secret weapon for poinsettia care: Poinsettias don't need to be fertilized during winter. If you plan on keeping your poinsettia plants year-round, then you will need to know about fertilizing them when spring arrives. Most people in the U.S. grow them as holiday annuals, though, so all you need to worry about is keeping them warm and watering them when the soil dries out.

Coffee grounds aren't deadly to poinsettias, but there are a few problems that come from improper use. If they're left laying on top of the soil, they may become moldy. It can also impact how much water and air are reaching the soil itself, so mix them into the soil well. Some gardeners may worry about the acidity of the coffee grounds, but that won't cause any issues for your poinsettia. That's because poinsettia plants enjoy slightly acidic soil, and the effect of coffee grounds on soil pH is frequently overblown anyways. Used coffee grounds are far less acidic than unused grounds, with the former having an almost neutral pH.

However, it can be a problem if you're relying solely on coffee grounds to fertilize your poinsettia plant. While coffee grounds can be part of an effective fertilizing routine, they don't contain everything your poinsettia needs to thrive. If you're only keeping them for the holidays, this is fine, since they don't need fertilizer anyway. 

If you plan on growing your poinsettia as a perennial, it will need other sources of nutrients, or else it may weaken and wilt. Composting your coffee grounds with other kitchen scraps is a great way to use your coffee as a fertilizer without ending up with a malnourished poinsettia. If you've never tried composting before, this step-by-step guide to home composting will help you get started.