Next step with cinder blocks/cement blocks?

loriemgross Posts: 5 ✭✭✭

I am confused between the Bio-Intensive Gardening course on here vs. the raised beds with cinder blocks shown in Marjory’s introductory webinar. I have made it this far now in prepping my beds… we had to clear HUNDREDS of these thin yaupon holly trees that you see in the background before I could even start!

The blocks are 8” x 2, so 16” high. I believe we are supposed have 24” deep of soil for this method. Do I (1) add another row of cinder blocks, one more high, to get to 24” with my purchased soil? Or (2) dig down 8” in rows as shown in the videos and add my 16” of purchased soil on top?

This is my very first attempt at any kind of gardening… I have no idea what tolerance for error there is, but I’m worried I don’t have a lot of time for figuring it out. Thanks for any help you can provide!


  • Torey
    Torey Posts: 5,408 admin

    Welcome to TGN's forum @loriemgross. That looks like you have put in a lot of work already!

    I'm not familiar with the growth habit of yaupon holly. Are these all young suckers off the bigger trees? They're not all bad, though. I've never had it but the leaves make a caffeinated beverage.

    Personally, I would dig down at least 8" into the existing soil, even if you are planning another row of blocks. It will help with drainage and root development for your crops as well as helping to prevent any shoots of the holly coming up in your bed (if that is how they grow). Are you doing more beds this year?

    Most plants are going to be pretty forgiving but there are some that are finnicky even for experienced growers. You will have your successes and failures like all of us. Its a life long learning experience about what will do well in your area and how you can push the boundaries of what you can grow. What are you planning to grow?

    You must be quite a bit south of me (Central BC, Canada), if you have this species growing. We have an introductions section where you can let us know where you are from and maybe make connections with others from your growing zone.

  • loriemgross
    loriemgross Posts: 5 ✭✭✭

    Thank you so much! I love BC, how wonderful! I’m in Bastrop, Texas, I think Marjory lived around here before, it’s very close to Austin.

    That answer was exactly what I needed. Please let me know if I missed something in the course work about the raised beds using cement blocks. I want to make sure I don’t need any other modifications or something like a liner or some sort.

    Once I get this bed all figured out I am going to do 2 more.

    The hollies grow like weeds here. The larger trees are post oaks. My husband says that they do seem to spread underground like you are saying. We’ll have to monitor that…

    I will introduce myself in the other forum. Thank you again!

  • marjstratton
    marjstratton Posts: 1,131 ✭✭✭✭

    I have raised garden beds and dug down on some of them before adding wood chips and adding soil and compost on top. We have voles which dig into our beds and eat and ruin our potato crops. My husband is planning to put down hardware cloth on the bottom of the beds when we rework them this spring. Not entirely sure how well that will work but we will see.

  • LaurieLovesLearning
    LaurieLovesLearning Posts: 7,218 admin
    edited April 2022

    @marjstratton Voles most likely can get through anything mice could. You are most likely best putting one smaller than 1/4" down in that case.

    @loriemgross When I did a raised bed, we put two things on the bottom before the fill. The first was hardware cloth for digging critters, & then landscape fabric to discourage the nasty grasses that like to invade everything, yet still give water drainage. Unfortunately, an ant colony moved in which I hadn't prepared for! 😖 There were so very many ants!

    Much later, I found out that spraying the box on the outside and around should discourage ants from invading the bed. I never tried it out, so I really can't say first hand how effective it would be.

    You could also put old trees & branches on the bottom as a hugelkultur addition. You will use less fill otherwise & it has its own benefits. I don't know how your holly would work in it (I don't have it where I live either). Some woods are fine, but I think there are a few that are not recommended.

  • loriemgross
    loriemgross Posts: 5 ✭✭✭

    Thank you, @marjstratton and @LaurieLovesLearning ! Very helpful!

  • JodieDownUnder
    JodieDownUnder Posts: 1,481 admin

    @loriemgross welcome to TGN. You’ve come to the right place to start your grow your own journey. Personally, I’d only go 2 cinder blocks high. Remember to fill in the cavities within the blocks too- extra growing space. Dig down a few inches & add some gravel etc for good drainage. Test the pH of your soil, depending on results, add lime or dolomite or sulphur. Then add manure, mushroom compost & top with mulch. Make sure you water each layer consistently.

    If you start with a good growing medium, it will make your experience better, keep you healthy & better for the planet. Put the work into the soil & it will look after you.