Black plastic vs. bare soil

[john]

I thought I would pass this along as I found this interesting.  I was just visiting the state of CT AG experiment station.  At which they do trials of new varieties and do experiments of all types of crops.  While I was there I visited with Dr. Abigail Maynard who is currently doing research on Okra.  She had several varieties that she was growing.  On half of the plot, she was growing okra on bare soil, on the other half it was on black plastic. The okra on bare soil was rather puny looking maybe a couple feet tall.   This okra did not exhibit branching at all.  It was bearing okra in fact Dr. Maynard had said  that it had started bearing a little bit earlier than the okra on black plastic.  But you could tell the yield on this okra was going to be significantly less thank the black plastic.
    The okra on black plastic was amazing.  All the varieties exhibited tremendous branching and the plants were husky and healthy.  It reminded me of Ron's patch of okra.  Both rows had been planted the same day and given similar treatment.  The only difference was the plastic.  I normally do not bother with the plastic as I am lazy and typically direct sow okra at the end of a few rows of corn.  This produces adequate results.  However, after seeing the vigor and beauty of the black plastic mulched plants I may have to work a little bit harder and lay some black plastic next year for my okra planting.  It looks like it will be worth it.

[heavyhitterokra]

John,

Make sure to provide a means of irrigation beneath the plastic. Black plastic gets really hot in summer. I've used black plastic some years and white plastic others, both with good results. Either is better than bare dirt. The plastic acts as a terrarium by recycling moisture. It also holds heat well into the night time hours to promote extra hours of growth during marginal weather.

[john]

Interesting about the white plastic still being beneficial. I wonder if that result would still play out here. (a much cooler climate than OK). Any idea why the black plastic grown plants exhibit lots of branching and the bare dirt did not. I would guess it would be a result of the warmer soil temps like you mentioned or could it also have something to do with greater reflected light up onto the plants?

[macmex]

Also, I have chatted with Glenn Drowns about plastic and sweet potato culture. Here, in Oklahoma, when my under-the-plastic-irrigation failed, I had a crop failure, since the sweet potatoes didn't receive enough moisture. Yet Glenn, in Iowa, never uses irrigation. He says the plastic holds the moisture in place and that everything does well! I guess it's a difference in climate.

At this time I'm moving away from plastic. I'm tired of having to remove it before I can plant again. I don't like finding pieces in my soil. However, whenever I counsel someone in a more northern location, wanting to grow hot weather crops, I suggest black plastic. Another great help for raising the heat level is a strategically placed wind break.

[john]

Interesting about the windbreak, do you think corn would make a good windbreak that could raise the heat level?
I am with you on the annoyance of black plastic. I hate to use it. For me it is a lot of work to lay it and then remove in the fall. If I had a mulch layer, I guess I might have a different opinion. I grow my sweet potatoes on bare soil. I am wondering about the difference in yield black plastic would make on them. How would you harvest them? The plastic would be a nuisance.

[heavyhitterokra]

I've used plasticulture on sweet potatoes before. The yield was higher but it cost about $35.00 per row to lay the plastic so the increased yield was eaten by the cost of the plastic. You have to destroy the plastic to harvest the potatoes. With some crops, like tomatoes, you can use the plastic again the second year. Any more than two years though, and you'll be hand digging and hand pulling 6" inch pieces of degraded plastic for the entire length and breadth of your rows.

On tomatoes or okra the labor saved by not having to pull weeds from tomato cages is way worth the cost of labor to install and remove the plastic. Plus the yields there are a lot higher, being how tomatoes and okra are a higher value crop than potatoes at the market.

I have a Plasticulture mulch layer though, so I kind of need to use it to justify having purchased the mulch layer. Plasticulture is not justifiable for use on every crop. Corn is one of those crops that doesn't pay off, potatoes is another. Green beans are "iffy" but if you use white plastic you can get in a Fall crop behind beans and corn. If you use black plastic, chances are your Fall crop will be killed by the "Chimney Effect" of hot air rising through the holes where your seedlings are planted.

No matter how you slice it, gardening is just a whole lot of hard work. Up until 2013, we were still plowing with a team of mules, raising our beds with the use of 16" inch concrete hoes, and laying our plastic by hand.

[heavyhitterokra]

Here are a few photos of my crops on black and white plasticulture. As you can see, it saves a whole lot of weeding, plus I can water it from underneath via drip lines hooked to my well.
 This photo was taken yesterday, May 23rd, 2018.  The okra shown above this caption is 32 days of age will be stunted due to night-time lows in the mid-thirties after germination on April 21st.  Sometimes I use black plastic, sometimes, I use white.  It depends on whether or not I think we'll be having a cold Spring or a warm Spring.  This year, Spring was wet and cold, so I used black plastic.



 This photo was taken in early July of 2015.  That was a year with a warm Spring, so I laid white plastic.


 This is how we used to do it back in the olden days.
This photo was taken in February of 2011.  (It was 2013 before we ever got a tractor).  Before 2013, we worked our garden with a team of mules.  This one was named, "Earl" he was the best of the pair.  Back then, we raised our beds by hand, with 16" inch concrete hoes. 

We laid our plasticulture each year, by hand, as the kids followed along behind us, covering the edges of the plastic with dirt, using shovels. 

We'd lay off fourteen rows of raised beds in a quarter acre garden, every year.  Back then, we were trying to pay my Wife's way through Law School by selling Certified Organic Produce to several restaurants, two grocery stores, the Tahlequah Farmers' Market, and the Tahlequah City Hospital.  We harvested around 2,500 pounds of produce from these beds each year.  The bulk of it was tomatoes and okra.

The beds were raised 8" to 10" inches high and were 24" inches wide. 
Our rows were 120' to 180' feet long, as our garden follows an old creek channel.  So we were laying a little over 1,600' feet of plasticulture by hand each year. Thirteen hundred and twenty feet is a quarter mile, so we'd lay a little over a quarter mile of plastic by hand every season.  You better bet it was worth the labor or we would have done it the easy way instead.  plasticulture keeps weeding to a minimum and allows me to water during drought conditions.

I grew the biggest okra plant I ever saw in my life, on black plastic in 2011.  We had 65 consecutive days over 100 degrees that Summer.  The last two weeks of that heatwave was over 110 degrees.  Agust 2, 2011 was 115 degrees.  Without plasticulture, I would have lost my garden in 2011.

[heavyhitterokra]

An OSU Professor, by the name of Lynn Brandenberger, did a pretty thorough report this year, on the three gardening trials he performed in the Summer of 2018. The three methods of planting he used in his Field Trial Study were:

Bare soil,

Plasticulture,

and
Paper Mulch.

I'll post the URL to his report because it is copy protected, so I couldn't paste any excerpts from it here for you to read.

www.hortla.okstate.edu/research-extension-youth/vegetables/pdfs/18vegreport.pdf

According to Dr. Brandenberger's 2018 Vegetable Trial Report, all the vegetables did significantly better on black Plasticulture than they did on either paper mulch or on bare soil.

The black plastic definitely has some sort of advantage, though after using black plastic since 2008, I still don't understand exactly what it might be, unless it's just the fact that the extra heat, early in the season really gives the young plants a much-needed boost.

[hedgeapple]

Aug 5, 2017 9:11:35 GMT -6 john said:

I thought I would pass this along as I found this interesting.  I was just visiting the state of CT AG experiment station.  At which they do trials of new varieties and do experiments of all types of crops.  While I was there I visited with Dr. Abigail Maynard who is currently doing research on Okra.  She had several varieties that she was growing.  On half of the plot, she was growing okra on bare soil, on the other half it was on black plastic. The okra on bare soil was rather puny looking maybe a couple feet tall.   This okra did not exhibit branching at all.  It was bearing okra in fact Dr. Maynard had said  that it had started bearing a little bit earlier than the okra on black plastic.  But you could tell the yield on this okra was going to be significantly less thank the black plastic.
    The okra on black plastic was amazing.  All the varieties exhibited tremendous branching and the plants were husky and healthy.  It reminded me of Ron's patch of okra.  Both rows had been planted the same day and given similar treatment.  The only difference was the plastic.  I normally do not bother with the plastic as I am lazy and typically direct sow okra at the end of a few rows of corn.  This produces adequate results.  However, after seeing the vigor and beauty of the black plastic mulched plants I may have to work a little bit harder and lay some black plastic next year for my okra planting.  It looks like it will be worth it.

This is my first year using plastic row covers (black) in my garden and I have noticed a few things already aside from the obvious absence of weeds and grass. Fewer insect pests and slightly different behavior by my plants.

In particular, all of my okra varieties, even those not known for branching, are coming in stocky and with branching. In fact, one variety I planted specifically because I wanted a non branching row in that spot, is doing so anyway. Very interesting. We’ll see by the end of this month if there is actually an insect benefit. Would be nice if I could get away with one summer without vine borers. 😊