The best thing about DIY organic fertilizers is that you're using ingredients you already have around the house. The items that you thought were garbage can now become plant food and, at the same time, save some space in landfills. While natural, organic fertilizers are generally safer for you and your plants, be aware that too much of a good thing could damage your garden. Start out small, and don’t use all the recipes listed below in one area.
Test Your Soil to Find its Nutrient Content
Have you ever noticed how green your lawn is after a thunderstorm? It's because the rain and lightning release nitrogen into the ground. Your plants need nitrogen, phosphorus, and potassium. These are the three ingredients that you will find in store-bought fertilizers and they're what the NPK stands for on fertilizer packaging.
In a fertilizer marked 20-5-5, there is four times more nitrogen (represented by the number 20) than phosphorus or potassium. Nitrogen dissolves quickly and is the number one ingredient that plants need most, which explains why most store fertilizers have more nitrogen content than anything else.
Before you go about making your own fertilizer, test your soil to discover what nutrients it may be lacking. Test kits can be found at most home improvement stores that have a garden area. Use your results to determine which methods you should use below to supplement the soil. Remember, as mentioned above, use fertilizers sparingly until the soil tests healthy again.
Easy One-Ingredient, One-Step Recipes
Hair. Yes, I said hair. Any kind of hair—dog, cat, or human—will have natural nitrogen in it. The easiest way to "harvest" hair for your homemade fertilizer is to clean out your brushes. Scatter the hair around your plants and rake it in just enough to keep it from blowing away. (A second benefit to having hair in your garden is that it will keep deer away.)
Other nitrogen-rich suppliers include coffee grounds and egg shells. To use coffee grounds, first spread them out on a cookie sheet to let them dry after making your daily brew. Then, spread them on the top of the soil in your landscaping. You can also make a "tea" with coffee grounds by placing about three cups of used grounds in a two-gallon bucket of water. Let the concoction sit for three or four days and then use the water to juice up your plants.
To use egg shells, first wash them thoroughly and let them dry. (I keep cleaned shells in a plastic bag until I have enough for a treatment.) Then, you can either crush them with a rolling pin or use a food processor to grind them. Spread the shells near peppers and/or tomatoes and work them into the garden bed. An added benefit of egg shells is that they help control blossom rot.
Reuse water from steaming vegetables. Let the water cool in the pan and instead of dumping it into the kitchen sink, pour it near your plants. Think of all that nitrogen you used to throw down the drain!
Old-fashioned matches that you must strike to light have magnesium in them, which is another beneficial element for plants. To reuse matches, all you have to do is soak them in water for a bit until they dissolve, and then pour the water near your plants. You can also just push a couple matches into the ground and let Mother Nature do the rest.
Does your soil need some potassium? Banana peels are just the cure. When planting, place a peel or two in the bottom of the hole before inserting your plant. In an existing garden, place the peels near the plant and cover with mulch. As the peel disintegrates, it releases all of its potassium back into the ground for your plant to use. Roses and azaleas love banana peels.
Powdered milk mixed into the soil before introducing plants will help even out the acid/alkaline content of your soil. Don’t use liquid milk—you will attract unwanted pests and it gets sticky. Besides, powdered milk is more concentrated and will do the trick faster.
Vinegar is a natural cleaner, antiseptic, mold reducer, and now a fertilizer. Mix either white vinegar or apple cider vinegar in a ratio of one tablespoon vinegar to one gallon of water. Pour over your plants, but use this method only once every three months or so—you don’t want to kill all the good bacteria.
I use gelatin on my houseplants once every couple of months. I dissolve one package of gelatin (not Jell-O) into one gallon of tepid water. It works wonders to keeps the leaves greener and the plant healthier.
Grass Clipping Tea
Unless your whole yard is a garden, I am sure you have some grass clippings lying around. Use the clippings to re-capture some of nature’s natural fertilizers. Fill a five-gallon bucket 2/3 full of grass clippings and then fill the remaining space with water. Let the bucket steep for about three days, making sure to stir it once a day. On the third day, strain off the water (which is now "tea") into another bucket (and discard the clippings into your compost pile). Mix one part clean water with one part of the tea mixture, fill into spray bottles, and apply the mixture onto the leaves of your plants. (It doesn’t matter if a few weeds get in with the clippings; weeds have nutrients, too.)
Compost tea is another way to use natural ingredients into an easy-to-use spray for your garden. Fill a five-gallon bucket 1/3 full with completely cured compost. Fill the remainder of the space in the bucket with water and let it steep for three or four days. Stir the tea often; several times a day is best, or it may start to ferment. After the third or fourth day, strain the liquid through cheesecloth and then dilute the compost tea by using one part tea to 10 parts water. Again, this fertilizer is to be sprayed onto the leaves of your plants and should last you quite a while.