from Hacker News

Rockwool vs. Perlite vs. Hydroton vs. Soil

by namidark on 10/5/14, 6:12 PM with 7 comments

• by nkurz on 10/6/14, 1:05 AM

  Nice comparison, but I think he missed the best option: Diatomaceous Earth (frequently abbreviated DE). It's been used for Bonsai for a while, but some tomato growers have been excited by it for a few years now: http://www.tomatoville.com/showthread.php?t=22329

  I used it this year, and think it's great. Ph neutral, sterile, cheap, non-hazardous, holds water but allows oxygenation, low environmental impact, pleasant to work with, and locally available. It can be purchased from chain auto parts stores as an oil spill cleanup (http://www.oreillyauto.com/site/c/detail/MTA4/8925/N0431.oap) and sometimes from Dollar Stores as kitty litter.

  Well worth trying if you are starting seeds or rooting seedlings. If buying for the first time, note that you do _not_ want "food grade" DE, which is a fine powder. The seedling stuff is more like fine grained cat litter. And you want to be sure you aren't buying a clay product instead, since some have similar names. Ultrasorb, Optisorb, or Blue Ribbon DE Premium Cat litter are brands to look for --- make sure it explicitly says "diatomaceous earth" or DE.

• by kolev on 10/5/14, 8:42 PM

  How about nutrition profiles? We've seen huge vegetables and fruits at the super markets, but their profiles suck compared to conventionally-grown, but usually smaller plants. If we only focus on rapidly growing biomass sold per weight ignoring the main reason we need plants - their nutritional benefit, we're going nowhere. Also, we know from some research that the more a plant has so struggle, the better its micronutrient profile is. Such example is the connection between grapes, climate, and resveratrol content.

• by sergers on 10/6/14, 1:08 AM

  If I needed a medium to nurture root structure a and retain some water/air, coconut coir all the way