Hard soil in my container and houseplants. What is causing this?

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I have several houseplants that I put out on my deck when the weather was nice. I've noticed that the soil in these containers gets rock hard and sometimes the water runs right out of the pot when I water them. This happens in a few of my plants that I've NOT put outside as well. I always start out with potting soil - Miracle Gro Moisture Control or regular mix. I think I am more likely to over water plants than to under water. I can't figure out what the problem is. I was thinking it has something to do with them being outside and the weather, rain and stuff but I can't explain the ones inside that get hard. Any ideas??
  7 answers
  • You are on track for your own answer~the outside weather and even old potting soil will harden especially when it has the stuff in it for moisture control. I do not use Moisture Control potting soil. I just use Miracle Gro basic or sometimes with fertilizer and find this works for me best (and I have lots of indoor and outdoor plants!) I do not use the StaGreen potting soil either~it is terrible stuff. Spring time is best to transplant and then get some good potting soil without all the "fluff". Good luck.

  • Irish53 Irish53 on Jan 28, 2014
    the chemicals is the water builds up in soil. It is good to change the soil more often in potted plants. Soil also settles over time so it is good to loosen it just like the outside garden soil that gets raked or hoed it keep it loose.

  • Douglas Hunt Douglas Hunt on Jan 28, 2014
    Your soil has become "hydrophobic," probably from drying out too much at one point or another. Walter Reeves has a suggestion here: http://www.walterreeves.com/gardening-q-and-a/potting-soils-saturation/

  • Lyette Lyette on Jan 29, 2014
    good information Doug, I will use the soap

  • Teresa D Teresa D on Jan 30, 2014
    Thanks guys. Too cold to try anything now. I'll just wait until spring which, according to the weatherman, may be just around the corner!

  • Kristy Cox Kristy Cox on May 14, 2020

    I know it's been 6 years since anyone has looked at this thread (give or take 1 or 2) but I wanted to thank everyone that replied to this question. I came across this thread from having a similar problem. I'm a 40 year old single mother and I try every couple of years to start a small garden but I can not ever grow ANYTHING!!! I can keep adult plants alive if given to me as an adult, but helping a new baby plant thrive is hopelessly lost to me. I can grow 35% of the seeds I plant into small plants but once they reach between 4-6 inches tall they wither and die. Yet here I am, trying again! But my soil looks like mud. I did not over water my plants and the soil is brand new, Miracle Grow moisture control (I know now thank you, C Renee, not to use moisture control) and 10-15 hours after watering the soil is hard and packed together and cracking on the top. Any suggestions? Thank you everyone!

    • Claire F Claire F on Nov 14, 2020

      Hi there,


      I may not be able to answer your question, but I have found YouTube to be a WONDERFUL resource for improving my green thumb. A lot of the plant experts on there all say any water retention soil is bad bad bad due to the gel composition in the soil.

      The gal on Planteria’s YouTube offers wonderful advice and tips for anything from growing plants, plant care and watering basics, all of that good stuff. You can dive into the rabbit hole of plant videos and learn so much. Hope this helps.

  • Bernice H Bernice H on Aug 24, 2021

    Wow! Just reading this! Yes my soil hardens also and water goes right through! Sooo frustrating,but now I am aware!