We’re Moving!



The Solana Center is excited to announce a move to a new blog: “Fresh Perspectives”. In an effort to better capture the diverse interests of our staff and audience, we have created a forum for all things sustainable at solanacenter.wordpress.com. Check out our recent posts and our latest rotline: “What are the white things in my worm bin?” by clicking here.


Yes! Thick, fudgy castings are as viable a soil amendment as finer, more granular castings. Denser castings can pose some challenges to the traditional methods of harvest and application. First, an important distinction:

–          Vermicast/Castings = Worm manure

–          Vermicompost = Amixture ofworm castings and decomposed or partially decomposed organic matter that has not been digested by the worm.

Worm castings are naturally a more concentrated substance than other types of compost, including vermicompost. Castings are generally characterized by their dark brown color and soil-like appearance, however, color, texture, and density will vary according to the inputs and care regimen of each bin. Thick castings signify a greater density of castings to vermicompost, but very thick castings tend to be a result of allowing excess moisture to build up in the bin.

–          The type of bedding used in the worm bin will affect the ultimate texture of the castings; for instance, coconut coir bedding will produce fluffier castings than shredded paper bedding.

–          The moisture content of the bin is critical in determining the final consistency of the castings: lower levels of moisture (and regular aeration) will produce lighter, fluffier castings, whereas allowing excess moisture to remain in the bin will clump materials and generate heavier, denser castings.

–          Clogged drainage holes are characteristic of a bin holding excess moisture. When drainage holes get stopped up with castings, standing water in the bottom of the bin causes the (highly-absorptive) castings to become very fudgy, thus making harvesting more difficult.

–          Castings that are left in a bin too long (and undergo multiple instances of digestion) will become increasingly condensed. With time, this over processing produces less nutrient-rich castings, less active worms, and can even become toxic to the worm community.  If this is the case, castings should be harvested as soon as possible.

When it comes time to harvest a bin with high-density castings, drying out fudgy materials is not recommended, as the process will be time-consuming (due to the high moisture content of the castings) and will likely produce hard chunks that are difficult to mix into the soil. Instead, use your castings straight out of the bin, or consider making worm tea out of some of the castings. 

Castings are generally mixed into the soil at a 4:1 soil to compost ratio, but it is worth noting that dense castings can be mixed into soil at smaller ratios, as thick castings have a high moisture-holding capacity, but are less permeable than fluffy castings or vermicompost.

Happy Composting!

The simple answer is yes, succulents can be composted, but there are some things to consider prior to throwing them in your compost pile.  Succulents can propagate from cuttings and/or leaves so you might end up with succulent volunteers coming up out of your compost pile, or even in your garden after you’ve utilized your finished compost.  If you have a hot compost pile, then volunteers should not be an issue.  If you do not have a hot pile, it’s recommended that you shred or chop up your succulents before composting them.  Given the high water content of succulents you’ll want to make sure and add some “browns” to your bin to balance out your moisture level.  Also, if you are composting spiny cacti, then you will have to take care when handling it.  The spines eventually decompose, but until they do, protect your digits with gloves!

Summer is here! 2012 looks like it has another hot, dry summer season in store for San Diego. It is important to protect your valuable composting worms from high temperatures and dry conditions. Red wrigglers cannot leave our vermicomposting bins to escape the heat, so it’s up to us to keep them cool during the warm summer months. Here are a few tips:

  • Keep the worm bin out of direct sunlight by placing it under shade, in the garage, on the patio or even inside the house (especially when temperatures exceed 100 degrees)
  • Keep the bedding evenly moist with water but be sure the bin is also draining properly. You may need to add water periodically during the summer months.
  • Consider freezing food scraps before adding to the bin during especially hot periods.
  • Remember that it is the internal bedding temperature of the bin, not the ambient temperature that is relevant for worm comfort.
  • Discourage ants, which tend to be more active in summer, by keeping the area of the bins free of debris, ensuring moist bedding, and putting the bin legs in dishes full of water.

These tips will help keep your worms cool and happy this summer!

by Asha Kreiling

Curing compost is the process when heat in the compost pile dissipates and the ecology of the microbe population changes. Certain kinds of soil bacteria, such as azobacteria, take over and produce high amounts of nitrates (which plants need to grow) and balance the carbon-nitrogen ratio of the compost pile, which is important in making nutrients available to plants. Decomposition of the compost material slows down, but continues to occur while the diversity of microorganisms increases.

Using uncured compost can potentially harm plants due to its unstable nature. Uncured compost may contain high levels of compounds like ammonia which can weaken or kill plants, by making soil too acidic. Adding uncured compost to soil can also reduce the amount of nitrogen available to plants, because as microorganisms continue to break down material that has not fully decomposed, they take up nitrogen in the soil for their own growth. In contrast, cured compost contains more nitrate and less ammonia due to longer maturation and mineralization. Cured compost is also more stable, meaning it will not become hot or increase in respiration when watered or turned as unfinished compost does.  Phytoxicity, a toxic effect on plant growth, can be caused by compost that is not stable or fully matured.  Phytotoxins can cause decreased oxygen and nitrogen levels in the soil, making it harder for plants to grow.

Read back on our old blog on how to cure compost: https://solanacompost.wordpress.com/2009/02/25/rotline-question-of-the-week-what-does-curing-compost-mean/







The Solana Center for Environmental Innovation is offering free composting workshops around San Diego County in February 2012.

Composting is an important component of environmentally sustainable communities because it diverts valuable organic matter from landfills and reduces the amount of waste that must be transported from neighborhoods to waste disposal and processing facilities. For residents, composting is also an excellent way to enrich soil in gardens, yards, and planters. Amending soil with compost can conserve water, reduce the need for fertilizer, and increase plant vigor and pest resistance.

Saturday, February 4, 10:00 am-12:00 pm, Water Conservation Garden: 12122 Cuyamaca College Drive West, El Cajon

Saturday, February 25, 8:00 am-10:00 am, San Diego Zoo (Otto Center): 2920 Zoo Drive, San Diego

Saturday, February 25, 10:00 am-12:00 pm, Crestridge Ecological Reserve: 1171 Horsemill Road, El Cajon (Crest)

These workshops are sponsored by the County of San Diego and the City of San Diego.

To register or for more information click here!

 Join the Solana Center for a FREE composting workshop at the Water Conservation Garden in El Cajon! The workshop will be held on Saturday, February 4 from 10am to 12pm. Click here to register and find out more details. If you have any questions regarding the workshop or composting call (760) 436-7986 ext. 222 or email compost@solanacenter.org.