I wouldn't follow any of these practices for a variety of reasons. Coffee is actually phytotoxic (so is tea), and watering with vegetable water (or water from aquariums) encourages gnats and algae. If a grower doesn't have a good nutritional supplementation program in place, vegetable water is very unlikely to be of any help. If you DO have a good nutritional supplementation program in place, adding whatever unknown nutrients that might be in vegetable water has much more potential to be a bane than a boon.

Al

Without knowing what kind of soil or potting mix is in your pots, your repotting regime, whether or not that's all you're giving the plants, there's not enough info to predict the wisdom or folly of this idea. Different foods would leave different substances in the water, and some, like coffee, could have a PH variance that would either be good or harmful to various plants.

I would recommend taking some notes and, of course, moderation in your experimenting. I'm always fascinated by organic ideas such as this, but rarely organized enough to follow through. This one is especially difficult because I certainly don't cook the same foods every day, hope you don't either! There are still many people who divert their kitchen sink water directly to a garden bed instead of down the drain BUT that's not an enclosed container environment. That's the difficulty when trying to apply organic techniques to potted plants. If you OD with something, there's no other surrounding soil to moderate the effects, likely insufficient microbial activity as well.

You might enjoy this discussion.

Hi there!

I have never used cooking water on my houseplants. I wouldn't want to risk it. However, I do pour my water from steaming or boiling vegetables on my outdoor plants. My rose bush outside my kitchen door is the most beautiful one I have. It seems to thrive on the water from the kitchen. Sometimes, I may also pour the water on the compost pile if it is especially dry.

I will add that the vegetables that I cook are all organic and come straight from my own garden. That might make a difference.

I do not drink coffee so have never used it on plants. We never have left over tea. Always an agrument over who put the empty pitcher back into the refridgerator, instead of making more.

Purple, I read the thread that you linked to here. Gotta love someone who uses a word like "wonky"! :)

Happy Friday to all!

Sarah

LOL, Thanks, Sarah! Happy Friday to you too!

Back when I had aquariums set up I used the old tank water to water my plants all the time, for many years, there were never any problems.

As long as you've got your plants in the proper type of loose, fast draining soil and have good watering practices you should too.

As far as your cooking water goes, I don't believe it equates to liquid compost. In compost the nutrients are broken down into usable forms by microbial processes which are not happening when you just boil or steam your veggies.

What is possible to happen is that the biota in your soil can break down what-ever is in the water and you'll get that "swamp gas" sorta smell coming out of your plants while it degrades. Coupled with the inconsistent moisture levels in potted plants which would start and stop or slow the process it seems like something you should be doing indoors.

I suppose this is potentially a problem with aquarium water but there should already be bacterial breakdown of wastes in the tank and filter(s) which should mediate these issues making the water closer to a weak compost tea.

It is still kind of a hit or miss method of fertilizing your plants, you don't have any way of knowing what is really in there.

One of my mum's friend never water her orchids with anything but whatever tea is left in the cup, before making a new cup. And they look amazing! -Granted they are all phalaenopsis, so not the hardest to grow, but still, they often produce 4 or 5 stems, so she must be doing something right (I don't know what tea she drinks).
Water from potatoes contain loads of vitamins, and is healthy for us to drink, so is the water from most greens. -I doubt the plants are able to absorb the same vitamins and minerals as us (without having any knowledge on the matter), but perhaps they can use some of them, or some that we can't use.
Why not make an experimental windowsill with some plants to try it out on, AFTER taking cuttings, and putting them somewhere else, so you don't accidentally experiment on them as well. Then watch them for a season, and see how they do? -Personally I can't join you in this adventure, as I never boil or steam anything, besides pasta and rice.

Forum discussions frequently center on the question of adding dilute coffee/tea or grounds to plants as a 'tonic', but Arabica (coffee) and Camellia (tea) are known for their toxic alkaloid (caffeine) content and their allelopathic affect on plants as well as autotoxic (poison to their own seedlings) effects on future generations. Caffeine interferes with root development by impairing protein metabolism. This affects activity of an important bio-compound (PPO) and lignification (the process of becoming woody), crucial steps for root formation.
We also know that the tannins in both coffee and tea are known allelopaths (growth inhibitors). There are ongoing experiments to develop herbicides using extracts from both coffee and tea that cause me to want to say they might serve better as a nonselective herbicide than as a tonic. I would not use either (stale coffee or tea) by applying directly to my plants - especially containerized plants; nor would I add tea bags/coffee grounds to my container soils.

I look at nutrition methodically. I prefer to use the least number of nutrient mixtures that will ensure my plants are getting all the essential nutrients they normally take from the soil and in the right proportions. The reason is, supplying more of any one element than a plant can use can be as limiting as supplying too little. 'How did he get THERE?' you might ask. What is in water left over from cooking vegetables - anyone know? So - you use it ..... then what? Obviously, it is going to be entirely inadequate in supplying the major elements, N P K Ca Mg S. So what do you do .... you fertilize anyway - because you have no idea what you supplied with the fish emulsion and you still need to be sure all the bases are covered.

The point is, if you're using fertilizers that only cover a few of the elements required for growth, additional fertilizers are required to fill in the gaps, Almost always, there will be overlaps, where you are supplying the same element in both products, or the same element will be missing from both products - gaps. Why not choose a fertilizer that supplies ALL the elements required for normal growth, and in a ratio to each other that is favorable, thereby eliminating gaps, overlaps, and potential antagonisms? (Antagonistic deficiencies occur when an excess of one element in the soil solution prevents adequate uptake of 1 or more other elements. Common antagonisms exist between Fe/Mn, P/Fe and Mn, Ca/Mg, others.)

I'm not saying the veggie water is particularly harmful, only that if you're employing a fertilizer like Foliage-Pro 9-3-6, it's probably redundant. This question in another form often comes up when discussing the use of aquarium water as a nutrient source. We know the aquarium water is not a complete fertilizer, and since you have no idea what you DID supply when you used it, you will certainly need to fertilize anyway - thus making the aquarium water (or manure) of little or no value.

The easiest and most efficient way to supply nutrients to your plants is with a soluble synthetic fertilizer that supplies nutrients in a ratio the same as the ratio at which the plants actually USE the nutrients. The only reliable way to do that is by using a fertilizer like I just described. When you depart from that plan, there can be no potential for benefits - only limitations that arise from either to much or too little of one or more elements essential for growth. Even if the residual veggie water supplied a nutrient necessary for growth, it would not help with growth unless it was supplying the single nutrient most deficient.

Al