People Are Pouring Pasta Water on Their Plants, But Experts Say There's a Better Option

Pasta water as plant food keeps popping up on social media. The idea makes sense at first. Why dump nutrient-rich water down the drain when plants could use it? Seems pretty resourceful and eco-friendly. But the reality isn't quite as clear.

Most pasta water contains way too much salt for plants to handle. Even a teaspoon of salt per gallon builds up in potting soil over time, eventually killing plants as concentrations reach toxic levels. The starch from pasta can create problems, too. It sits on the soil surface and grows fuzzy mold that looks gross and attracts fungus gnats.

Following basic garden watering principles means avoiding salty water, regardless of any other potentially beneficial nutrients dissolved in it. Instead of following this less-than-ideal online hack, I'll share three alternative types of cooking water you can use to give plants a boost.

Why Pasta Water Isn't Good for Plants

Salt is the main issue here. Most people salt pasta water heavily – the classic Italian instruction is to make it "taste like the sea." That's perfect for pasta, but terrible for plants. Salt doesn't break down in the pasta water or your soil. When salt accumulates in the soil, eventually concentrations can get high enough to burn roots and block water absorption.

Starch creates surface issues, too. As pasta water cools and sits on the soil, the starch from the pasta forms a film that dries into a crusty layer. This layer feeds mold and bacteria, creating fuzzy white or gray growth. The crust blocks water penetration as well. Even unsalted pasta water has enough starch to cause these issues over repeated use. So skip the pasta water when it comes to plants.

Pasta Water Alternatives

Plain tap water or rain water works fine for most plants. The benefits from cooking water are minimal. You're not going to see dramatic growth differences compared to regular watering.

If you really want to boost plant health, use actual fertilizer at the proper dilution rates rather than relying on cooking water to do the job. And use a fine tip spout watering can, like this one from Amazon, to make applying any water easier without spills.

The cooking water trend is more about reducing waste than revolutionizing plant care. If it makes you feel better about dumping less waste water down the drain, go ahead and try one of the following alternatives. Just don't expect miracles. And definitely skip the pasta water, regardless of what the latest social media gardening trends and your favorite PlantTok videos say.

1. Unsalted Vegetable Water

Leftover water from boiling unsalted vegetables outperforms pasta water easily. Potatoes, carrots, spinach, broccoli – nearly any vegetable releases water-soluble vitamins and minerals during cooking. Plants absorb these readily without salt complications. Beans, peas, corn, and asparagus add their own traces, too, broadening the nutrient mix.

Cool cooking water fully to room temperature before applying to plants. Hot liquid scalds roots. Nutrient profiles vary depending on the vegetable. Leafy greens contribute nitrogen for foliage. Root crops add potassium and other trace nutrients for overall vigor. Starchy veggies, like corn, release small carbs plants use for trace organic compounds and minerals.

Benefits are modest compared to fertilizer, yet this kind of cooking water is an improvement over plain tap and reduces kitchen waste at the same time. Apply within a day or two after cooking. Longer storage risks bacterial growth and bad odors. Strain out solids if chunks remain to avoid clogging drainage in potted plants.

2. Egg Water

Water used to boil eggs picks up trace calcium that's leached from shells. Calcium strengthens cell walls in plants and supports structural health. The actual amounts of calcium are small – and insufficient for major deficiencies – but egg water can provide a gentle supplement that plain water can't. Hard-boiled or soft, the calcium leach happens either way when boiling eggs.

Cool water completely before use. The advantage is subtle yet worthwhile, repurposing water that would otherwise be discarded. Egg water benefits calcium-sensitive crops like tomatoes and peppers, which are prone to blossom end rot.

Most houseplants require less calcium, but still benefit from occasional additions of this nutrient. Combine with vegetable water for broader feeding, if using it on multiple plants. Use a plant food like this balanced fertilizer from Amazon for more consistent nutrition.

3. Rice Water

Rice rinsing water – the cloudy liquid that comes from pre-cook washing – differs from rice boiling water. It holds proteins, lighter starches, and minerals without heavy residue. Brown rice rinse water adds extra bran nutrients compared to white rice.

Some people ferment it a day or two at room temperature to enhance the availability of nutrients, though evidence of the benefits of this practice are limited. Fresh rinse water performs adequately without fermentation. Apply immediately to plants or refrigerate to maintain quality. Dilute if cloudy and thick to avoid temporary soil clouding.

How to Use Cooking Water on Plants

Cool all cooking water to room temperature first before pouring it on plants. Hot water damages roots severely and cold water stresses tropical houseplants that are accustomed to warmer soil.

Treat cooking waters as enhanced regular watering, not fertilizer substitutes. Nutrients are light relative to dedicated fertilizers. Water plants thoroughly until it flows out of the drainage holes, then empty saucers after 30 minutes to prevent root rot. Rotate cooking water types to vary nutrients.

Common Mistakes to Avoid

Avoid salted cooking water entirely. Salt accumulates steadily regardless of the initial amount added when cooking. Discard water from salted vegetables or pasta.

Pass on pasta water, even unsalted pasta water. The starch from pasta promotes mold and pests in potted plants. Skip broths or flavored liquids with herbs and spices that might imbalance soil microbes, too. Reserve those for drain disposal. Limit to unsalted vegetable, egg, or rice rinse waters for safe, effective recycling on your plants.