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.