Keep Compost Away from Young Plants

Q. When I apply compost to plants, do I avoid the main trunk area or do I apply up to the trunk?  

A. If soils have no plants in them, I use about 1 inch layer of compost applied to flowerbeds and vegetable beds every year. This compost is turned under or rototilled into the soil before planting. 

Compost can be used as a substitution for fertilizer in vegetable and flower beds even when plants are actively growing in them as long as you can see bare soil. Apply the compost to the soil between the plants or between rows and water it in. 

Compost can be applied to the soil surface and watered into the soil and act like a fertilizer

Compost can be applied to fruit trees in a circle around the trees under the canopy where the soil is wet. The compost should not be piled against the trunks of the trees. 

Compost can be added around fruit trees to the soil surface but keeping in from contact with the tree directly and then watered in. It is very effective when combined with a surface layer of wood chips.

Compost can be applied around desert landscape plants on top of coarse rock mulch. If the rock is coarse enough, it can be washed onto the surface of the soil under the plant canopy through the rocks with a hose. It is best if straight compost does not come in contact directly with soft succulent plants or young trees.

Compost tea brewer, top, and applying compost tea with an injector directly into the soil.

Compost can also be put in with pure water and allowed to "seep" just like tea in a tea bag. The water separated from this combination, compost tea, can be used as a liquid fertilizer and in some cases helps reduce disease problems in the soil or when used as a spray on the foliage.  After the tea has been made the compost can still be used as a soil amendment, but, of course, wit;h a lower nutrient content.

Be careful, though, the type of compost used can make this tea solution very concentrated and can harm plants unless it is diluted with water. It is good to use a salinity meter to judge whether it is safe to apply to foliage directly without dilution or knowing how much to dilute it. The salmity of the compost tea should be below 4 mmhose/cm or dS/m. 

Compost Should Finish Its Cycle before Application

Q. How do I know when compost is safe to apply to plants? Do I measure temperature?

A. Compost is safe to apply when the composting process has completed. Look and smell a compost to see if it is finished. A finished compost will have the same color throughout and the components are not recognizable. Everything looks the same.

Finished compost should have a dark color, the color should be consistent through the compost and the components used tof composting are not distinguishable. 

Commercial compost is safe to apply any time it has finished the composting cycle. Most commercial compost is never sold or marketed before it is finished. The components of a compost will eventually break down and supply nutrients to plants separately but there are some problems doing it this way.

Composting is the same process used by Mother Nature when things “rot”. But in composting, this rotting process is sped up and managed. If you are making your own compost, it is probably a good idea to purchase a compost thermometer.

The type of composting I would use is pile composting. This method mixes all the components together and puts it in a moist pile. The fastest way to get a finished compost using this method is by turning this pile or aerating it when the core of the compost reaches 160° F and wetting it down.

A slower method is the static pile composting method where the pile is never turned. There are much fancier ways of making compost like using forced air or in-vessel composting which can finish compost extremely fast.