Is it Safe to Fertilize and Water Plants in the Fall?

Q. Being I have several neglected outside plants that need attention, I cleaned their dead growth and replaced any soil missing with new potting soil.  Is it safe to fertilize and water this time of the year using Miracle Gro and tonic?

Miracle Gro was purchased by Scotts and some in sales say the quality has gone down among chemical fertilizers. As far as I am concerned, it is water soluble and carries the right combination of nutrients and low in toxic elements, who cares?

A. You didn’t tell me which plants you have, I don’t know which Miracle Gro fertilizer you want to apply, and I don’t know what the “tonic” means. To be on the safe side don’t apply anything to the soil or to the plants until winter temperatures warm up sometime in February or early March.

Plant tonics are not regulated and can contain anything the manufacturer wants to add. Make sure the nitrogen content of a plant tonic is low enough that you are not stimulating any late growth of winter tender plants.

To be more specific, if the plants are winter tender (freeze above 25F in our climate) then don’t stimulate any new growth with any nitrogen fertilizer. Wait it out until spring. Don’t apply any high nitrogen fertilizers (fertilizers with the first number on the bag highest) until late February or early March. The later you delay applying fertilizers during the winter the better. The same holds true of the “tonic” that you mentioned.

Super thrive falls in the category of a "plant tonic" in my opinion. It is not a fertilizer or it could fall under the states fertilizer laws and be regulated. Some "plant tonics" people swear by and some people swear at. If it contains nitrogen in the ingredients, be careful of stimulating late season growth if the plant gets an excess.

In the future don’t use “potting soil” to fill holes or empty spaces in the soil. Try to match well the soil you are applying closer to the type of soil surrounding the plant roots. Potting soil is usually too “fluffy”. If you already have this potting soil or can’t do this for some reason, then make sure potting soil is mixed well with the surrounding soil and then water thoroughly.