Soil Remediation in Hoophouse

Looking for some advice on what the soil in my hoophouse might need. We’ve been growing in this hoophouse for over 10 years and I’m thinking the soil maybe needs more than what we’ve been giving it. We add compost every spring (and sometimes during the season between crops), and use drip line irrigation and can normally get three plantings with fairly good harvest out of them. Often we can get an early brassica in there followed by tomatoes or cucumber, followed by greens.

The soil has gone unwatered all winter, and looks fairly blah- sandy, nothing growing. Last year I tried a late planting of zucchini in there and the plants were small and produced low amounts of fruit. Could there be a ph issue? I don’t know much about caring for the soil inside a hoop house. Any thoughts would be appreciated. Have not done a soil test.

@planborganicfarms? You guys may have some good advice?

That does seem like a long time to do continuous cropping in one spot without giving it a break. Is the hoophouse easily movable? You could move it over one length and try and rotate it at most every 2-3 years, then cover crop where it stood for 2 seasons before coming back to that spot.

If you can’t move it, consider giving it a break entirely if possible, or split it in half and give half of it a break and ammend the other half for use that year. 10 years in production have most likely altered the pH and you may also be running low on some macronutrients. Do you do soil tests on the farm? Consider doing a separate soil test inside the hoophouse to see what is really going on.

It sounds like your soil structure has degraded over the years and the soil may be low on OM, which is why I was suggesting you cover crop it and let OM build back up before using it again. Earthworms are usually the canary in the mine, if they aren’t there then it typically means there’s nothing for them to sustain themselves on. Do you see any of those little guys in there?

In the future, try to cover crop early in the season and also late in the season if your schedule allows it (unless you want cold season crops in there like spinach and others). You can keep ammending the soil but I’m not sure it would solve your problem over the long term. :confused:

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Number one: do a soil test. It will likely identify the problem; at the very least, it will eliminate a bunch of potential causes. It will be a much more efficient use of your time and resources than trying things out with partial information and the educated guesses of everyone here.

Does your hoophouse stay covered year round? If you’re not exposing the soil to the weather and only using drip irrigation, chances are salt levels have built up in the soil - this would be particularly true if you’re using a manure-based compost.

Compost is a great soil amendment, but it won’t necessarily replace the nutrients in the amounts and ratios that they are being removed by your crops. Over time (and 10 years of intensive cropping is certainly lots of time), your nutrient balance could shift significantly - some things (like calcium) may be deficient, others could be excessive.

pH could be an issue, but you need to know what’s behind it: calcium and magnesium (and to a lesser extent potassium and sodium) will all play a role - particularly in a hoophouse/greenhouse situation.

I’d also second the advice Denis gave about giving it a break and/or incorporating cover crops as long-term strategies. If you want to restore the productivity and health of the soil relatively quickly, you need the information that a soil test can give you.

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Thanks @dheraud and @rob! We were planning on moving it last month, but didn’t find the time so were going to try and get one more season. However, it sounds like we’re best to cover crop it and try and move it in the fall. Good things to keep in mind as we recently bought 2 more hoophouses going into production next summer! Thanks for the advice.

I might also consider taking the plastic off for a winter. There may be accumulated salts from the lack of rain and the high fertility inputs that this house may have seen. Being open to the weather will flush some of those salts and help with a “restart” of the house.

When getting a soil test, consider a saturated media test. Its the test that is more suited to potting mixes. Often the fertility in a greenhouse is off the charts when it comes to a standard field test, and the SM test is a better indicator of the situation in the house.