Should I add bagged manure to my potting soil when I plant tomatoes?
I plant my tomato plants in 100% horse manure every year with no problems, however if you are using bags of steer manure, do not use too much. It is too strong. I never use potting soil. Plants do not like it, because it has a lot of fillers such as wood chips. Couldn't you make some compost?
Potting soil is primarily peat moss with composted bark and perlite and sometimes vermiculite and sand. It has no nutritional value, although some do contain small amounts of regular or slow release fertilizer. Its primary attributes are its acid pH and resistance to plant pathogens. So, yes you can add bagged manure to the potting soil. However, the average amount of the 3 main plant nutrients found in cattle manure is rather small— 0.6N, 0.2P, 0.5K. Its main value is in stimulating beneficial bacteria growth in soil and thereby unlocking some nutrients. In addition to the main 3 there are a host of secondary and micro nutrients that are important to tomatoes. For instance, lack of calcium can cause blossom end rot. I suggest you add a fully balanced fertilizer or combination of fertilizers that address all the nutrient needs of tomatoes.
