How Does Peat Moss Affect Marigolds?

Marigold Needs

• Marigolds grow best in warm, sunny and loose soil reasonably high in organic matter. Soil amendments can help lighten heavy soil. Fort Valley State University (FVSU) Extension recommends preparing marigold flowerbeds by adding 3 to 4 inches of organic matter across the entire surface of the planting area -- pine bark, leaf mold, manure or peat moss -- and then digging it in and cultivating thoroughly. For heavy soils FVSU also suggests adding 1 inch of sand

Peat Moss

• Peat moss is included in FVSU's list of possible soil amendments because, like the others mentioned, it is a natural source of organic matter. It is highly valued by nurseries, other growers and home gardeners for seed germination and plant propagation because it is sterile and disease-free. It has an impressive capacity to absorb moisture -- like a sponge -- and then slowly release it. Yet the only sources of peat moss are very specialized wetlands known as peat bogs, which are critical for water purification and take centuries to form -- the largest terrestrial carbon store on earth. Once mined sphagnum mosses won't easily grow there again. Because peat is a non-renewable resource, many working in horticultural industries are rethinking its heavy use and seeking viable alternatives.

Effects

• The primary effect of peat moss in the soil when growing marigolds is helping the soil hold more moisture -- like all organic matter. Peat and other organic matter also helps improve the overall soil texture, lightening and loosing the soil so water permeates it more effectively. Like any organic material, peat also acidifies the soil somewhat. Unlike almost any other organic amendment, peat does not add any nutrients to the soil, and does not "feed" microorganisms that help break down other types of organic matter into usable plant nutrients.

Alternatives

• Peat is not easily replaced for sterile seed germination and plant propagation, but compost, manure and other organic materials can substitute for most other uses. In fact in some are superior to peat moss, especially when it comes to benefits such as plant nutrient levels, cost, recycling of organic waste and usefulness as mulch. Peat moss can't be used as mulch, because when dry it tends to attract and hold moisture -- and will "steal" rainwater or irrigation or pull it right out of the soil, defeating the purpose behind mulching.