Spring is just around the corner, so let us talk gardening. Interest in pawpaw (Asimina triloba) has increased in recent years. Pawpaw trees are native to Indiana, and have edible fruits with a unique aroma and flavor.

The nickname “Indiana banana” is often given to pawpaw because of its banana-shaped fruit, which is high in vitamins. Each ripe fruit contains two or three large, dark brown seeds. Each plant is either male or female, thus several trees are needed to make sure pollination occurs.

A common question is how to propagate the pawpaw from seeds. The seeds of pawpaw require special treatment. Remove the seeds from the fruit, and immediately store in the refrigerator in plastic bags filled with slightly moistened sphagnum peat moss. Leave in the fridge for three to four months, and then sow indoors in a well-aerated Pro or Metro mix at 75 to 85 degrees.

The seed can take up to 60 days to develop. Pawpaw shoots develop without the cotyledons (seed leaves) present in most plants. The seed also can be sown outdoors in a prepared area, but often can take two years to develop. Regardless of the method, never allow the seed to dry out completely. Pawpaw is a good candidate for growing in bottomless containers, because the roots are thick with few root hairs.

In the wild, pawpaw tends to form colonies like sassafras, and can be just as difficult to transplant. Pawpaws prefer rich, acid soils in protected areas with as much sun as possible for fruit formation. Some nurseries are beginning to offer pawpaw trees to homeowners. These trees are selected based on their superior fruiting characteristics. “Sunflower” is a cultivar often mentioned in the literature.

Banana Skins and Fish

No, this is not an entrée item from a restaurant in Beverly Hills – but I suppose it could be. They’ll eat just about anything out there. Gardeners always are looking for an edge, something that will make their plants grow better than the neighbors’. Yes, that’s it! Let’s use leftovers! You can just visualize the lightbulbs appearing over the heads of those with leftovers that have been tucked away in the refrigerator since 1959.

Turns out that some leftover food products have nutrients that plants could use. I have talked with a few gardeners who swear by banana skins. The enterprising gardeners either bury the banana skins near a favorite plant such as a rose, or simply place the skins near the plant to decompose. Turns out that banana skins contain about 42 percent potassium by weight, and about 3 percent nitrogen. Potassium helps plants develop strong stems, aids in drought tolerance and has minor roles in flowering. Nitrogen in general helps plants develop healthy leaves.

Hopefully, droves of monkeys won’t show up and dig around your roses.

Other leftovers also have significant amounts of plant nutrients: Grapefruit skins, for example, contain 30 percent potassium and about 4 percent phosphorous, which is helpful for root, flower and fruit development. Dead fish can contain anywhere from 2 to 7 percent nitrogen, and 1 to 6 percent phosphorous. Coffee or tea grounds can add nutrients to the soil, plus they also acidify the soil near plants. Even pine needles, my choice for mulching around annuals, can add nutrients to the soil.

American Indians used their leftovers long before modern gardeners began burying their banana skins near plants. Unused fish portions were the first “fertilizer” for maize. The only drawback to using leftovers as plant fertilizer is, of course, the critters. One might suspect that fish waste, bananas, grapefruits and such would entice critters such as groundhogs and raccoons to the garden. I guess this is a risk that some gardeners will take. One also could use putrefied eggs, which contain about 2 percent nitrogen and trace amounts of other nutrients in the garden. If you use rotten eggs for fertilizer, then expect the neighborhood deer population to spread the word to others that you are a gardening madman.

Contact Todd Hutson, Purdue University Extension educator in Vermillion County, at 1-800-340-8155, Ext. 147; or e-mail him at hutsont@purdue.edu.