Materials to use for Grow-Boxes – Or Why Not Grow Right In The Dirt??

Q.  We are starting a container, or Grow-Box project at an orphanage in northern Mexico. We are having a hard time finding saw dust or peat moss. There is soil conditioner available at a nursery for $3 a cubic ft. Is this a feasable alternative to mix with the sand?   Thanks. Dr. Don
A.  May I inquire first as to why you are not growing right in the regular soil?  If you’ve been told “nothing will grow there”, or “the soil’s worn out,” don’t believe it!  “SOIL IS SOIL”, as Dr. Mittleider often says, and what he is trying to convey is that you can grow great gardens in virtually any soil, anywhere in the world!!  Therefore, unless there has been a garden in that spot recently which was diseased, I would suggest you just make level, raised, ridged soil-beds and grow “right in the dirt”. 
The Mittleider gardening book Grow-Bed Gardens actually has pictures of great soil-bed gardens in Mexico, as well as many other places throughout the world.  It’s available as part of the Mittleider Gardening Library CD at
By using the balanced natural mineral nutrient fertilizers we recommend, your crops will thrive in any soil that is not toxic or diseased. The formulas are on the website, in the Learn section on the Fertilizer pages, and you can get them already mixed in the Material section of the Store – also at
If for some reason you really must use Grow-Boxes, because you have no ground, but only a driveway, patio, or rocks, then go for it.  But DO NOT USE dirt in the Grow-Boxes! 
And I DO NOT RECOMMEND soil conditioner as a viable alternative to sawdust and sand in your Grow-Boxes – especially at $3 per cubic foot.  There are three reasons I think of at the moment:
1) the cost amounts to about $90 per 30′ Grow-Box.  We are all about making gardening affordable to those who have very little money, and this flies in the face of that philosophy. 
2)  Usually, soil conditioners have small amounts of a few of the nutrients in them, but you rarely know what is there, and it is never just what is needed.  So it can actually do more harm than good if it creates an excess of any nutrient. 
3)  Unless you KNOW the source of the materials used in the soil conditioner – that they are all clean and free of diseases, bugs, and weed seeds – you run the risk of introducing problems from those sources into your garden.
I DO RECOMMEND you look for other clean finely ground-up organic materials that are available free locally, or at very low cost.  A few suggestions include 
1) coffee hulls,
2) rice hulls,
3) finely chopped coconut husks,
4) sugar cane refuse (Bagass, or the result after pressing the sugar from the canes),
5) leaves (but avoid scrub oak below 5,000 feet elevation and black walnuts), and
6) a really good option is pine needles (yes, these work great, and will not ruin your garden!). 
If you can find a hammer mill to chop the materials finely, any of the above will work well for you.  Have success, and don’t hesitate to ask questions!

Plants Not Growing – Being Detective to Find Out Why

Q.  I am writing in regard to some problems with the container “Grow-Box” method we are experimenting with here in southern Mexico. 

We built the box, mixed 3/4 sawdust and 1/4th sand, as well as adding the calcium and the fertilizer pre-mix before planting. 

At planting we added the first week’s fertilizer mixture and watered. 
We are experiencing problems with all our plants.  They just don’t look good at all.   The squash started good but then the older leaves seem to die prematurely.  
The female squash at flowering have the fungus that causes blossom end rot and many of the female flowers never reach the stage of opening up at all.  They start to get pale looking and shrivel up and die before they open. 
Our lettuce looks weak and isn’t growing well. It has good color but just seems to sit there and doesn’t grow.  We also planted green tomatoes that are not growing well.  They just seem to grow very slowly.  The Swiss chard is not growing as I had hoped it would either.
We have moisture and the plants have not wilted.  I don’t think there is too much water.  Other than the fungal problem on the squash we have had very little insect problem.  
Jim Wagoner, IMB Missionary to Oaxaca Mexico
A.  Let’s look at each element of the equation, to determine what is missing.

What are the materials being used – what kind of sawdust, and what kind of sand?  Is it new sawdust, or has it been used for something else before?  It can be new, but should not have been used for growing before.  Also, it should not be from walnut trees.
The program calls for mixing 2# of Pre-Plant mix PLUS 1# of Weekly Feed mix into the soil of an 18″ X30′ bed or box before planting.  Did you apply both, including Weekly Feed?  And are those the amounts you used?
You say you put Weekly Feed in when you planted – first of all is the Weekly Feed formula accurate?  Secondly, were you planting seed or seedlings?  When planting seed, you do not put any more fertilizer down until the plants are showing – then you feed 1# per 30′ bed.  Fertilizer applied at planting of seed, if it’s close to the sprouting seed, can kill the new seedling, or severly stunt its growth. 
When planting seedlings, we recommend applying 1/2# of 34-0-0 or other nitrate to a 30′-long bed immediately after transplanting, watering that in, and then starting the Weekly Feed regimen 3 days later.  Did you do that?
It is VERY rare to have a fungus disease in new sawdust/sand mix, unless it came with transplanted seedlings.  NEVER use seedlings grown by someone else!  If you’ve got it, you’ll have problems for sure. 
The problem is more likely caused by failure to be pollinated by the male flower, by stress, or lack of direct sunlight, water or nutrients.  A plant in stress will abort new fruit in order to try and stay alive.  Blossom-end rot is a classic example of stress due to uneven watering or lack of nutrients, such as calcium. 
If the leaves look healthy it’s very possible the squash problem is lack of pollination.  For squash plants, take a male blossom, tear off the petals, exposing the anther, and pollinate female flowers, by lightly touching the pistil.  Do this in the morning between 7:30 and 9:00, and only do it with blossoms that are wide open, as they are the only ones that are fertile.
How close to the plants are you applying the fertilizers?  And how are you watering?  Remember that sawdust and sand will allow the water to go almost straight down. 
Sometimes people apply the fertilizers 6″+ away from the stems of the plants, and the tiny roots never see any food, because it is washed down and out of the root zone, rather than flooding the root zone with nutrients, as should be done. 
Do you have full and direct sunshine all day long?  This is essential!  And are you really watering thoroughly?  You should see water coming out from the bottom of the box before you stop.  Remember, it’s almost impossible to water too much, but very easy to water too little.
Plants that are “just sitting there” and not growing vigorously are either sitting in the shade, where they don’t get direct sunlight for 8-12 hours each day as they need, or most likely they are lacking nutrients or water, or both.  Let’s get specific and see which of those three is in short supply.
By accurately following the illustrations and instructions in just one of Dr. Jacob Mittleider’s vegetable gardening books, such as Grow-Bed Gardening (available at, you can avoid these problems and have a trouble-free and successful garden.


Containers – Depth, Width, Materials & Drainage

Q. I’m building a large Grow-Box 3′ high 3′ wide 15′ long. We receive 10-12″ of rain per year; we have mostly clay soil. 1) I’d like to promote better drainage and have a 3″ soil augur. Is it better to fill my holes with a gypsum and soil conditioner mix or a gravel and gypsum? 2) I’m hoping to get some County compost to mix with sawdust, sand, gypsum and clay to fill the mankiller in disguise.

A.   A real drainage problem is almost unheard of when using containers, and especially in the dry country you describe.  If you must dig, fill auger holes with course gravel. More likely, you would want to preserve every drop of water for the plants, rather than expediting the drainage. For example, even without raised containers, by making level, raised, ridged beds right in the soil, and having the planting area an inch or so above the aisles, you will normally solve any drainage problem in the low rainfall area in which you live.

Why is your Grow-Box 3 feet deep? If bending over is a problem, I recommend 18″ or at most 2’.  If you like working in a Grow-Box rather than the soil, and low bending isn’t a problem, consider building it 8″ deep.  And for any depth box, fill with peat moss, sawdust, perlite, and sand, in equal amounts by volume.  Any combination is fine, so long as the sand is 25-35% maximum. 

Also, build it 4′ wide, rather than 3′, if you have the space. This size will give you 4 rows of most vegetables, while still allowing plants the light they need, while a 3′-wide box only gives you 2 rows.  Excellent detailed instructions for building Grow-Boxes are in most of the Mittleider gardening books, available at

You speak of gypsum as if it was a major ingredient in your soil mix.  In a Grow-Box 8″ deep X 4′ wide X 15′ long, apply just 2# of gypsum evenly over the surface of the soil under the Box before you fill with the planting mix. Then, after filling with the planting mix, apply another 2# evenly over the surface and work it into the soil mix.   After each crop apply 2# to the soil mix and work it in.

Perhaps you only meant to use the gypsum in the holes you propose drilling into the clay soil beneath the Grow-Box.  If that’s the case, I would use sand and gravel in the holes.

The Mittleider Gardening books and Manuals teach all you need to know about this subject, and can be purchased in the Store section, or as digital downloads. 

A digital copy costs 30-40% less, and is available instantly!  I HIGHLY recommend you look here for the best gardening books available anywhere!  Get one NOW and be gardening TODAY!!