Arizona Pepper Trial: 100% Transplant Survival and 39% More Root Mass with Multi-Tricho Trichoderma

A pepper crop is decided early. Transplant is the moment a seedling either takes hold or does not, and every plant lost in the first three weeks is a hole in the stand that produces nothing for the rest of the season. Root establishment sets the ceiling on everything after it: how much water and nutrient the plant can reach, how it handles a hot week, how many pods it can carry to maturity.

Under a standard nutrient program alone, that early window is where intensive pepper production leaks the most. Seedlings go into a root zone with very little biological activity, so the nutrients in solution are available but nothing is helping the root system expand fast enough to use them. Growers see it as uneven establishment, slow early growth, and a stand that never quite evens out.

This trial asked a narrow question with an obvious commercial answer attached: does adding Trichoderma to the root zone change transplant survival and root development when nothing else about the nutrient program changes. An independent laboratory in Arizona ran it across three growing systems, and in one of those systems added a third group treated with a leading commercial Trichoderma product, to see whether strain composition made a difference or whether any Trichoderma would do.

Multi-Tricho is an OMRI Listed multi-strain Trichoderma inoculant built from three species, Trichoderma harzianum, Trichoderma longibrachiatum, and Trichoderma asperellum. They colonize the rhizosphere and the root surfaces themselves, where they produce enzymes and metabolites that cycle nutrients and support root elongation and branching.

The lab ran three lots. Lot A grew in a standing hydroponic solution and was assessed three weeks after transplant, on root mass, root length, and survival. Lot B grew on drip and ran two months out to fruiting, measuring plant height and pods per plant. Lot C grew in soil for one month and carried the third group, a leading commercial Trichoderma product, alongside the untreated control and Multi-Tricho.

Every group in every lot received the same hydroponic nutrient solution made up with distilled water. The treated group got Multi-Tricho added to that base. The control got the base alone. Nothing else differed, which is what makes the comparison worth reading.

Two limits are worth stating plainly. The three lots are separate trials in separate systems at separate timepoints, not one experiment measured three ways, so the survival number and the pod number come from different plants. And the commercial benchmark was only grown in Lot C, where the measurements taken were height and leaf area. There is no benchmark figure for survival, root mass, or pod count, and we do not report one.

Every treated transplant lived. Twenty-four of 24, against 17 of 24 in the untreated control, a 70.8% survival ratio. Roughly three in ten control seedlings never made it out of the establishment window. On a commercial stand that is the difference between a full planting and one that needs gapping up.

The root data explains why. Treated plants carried 126.4 grams of wet root mass against 91.1 grams in the control, 39% more, and root length nearly doubled, 26 cm against 14 cm. A root system twice as long three weeks after transplant is reaching water and nutrient the control cannot get to, which is exactly the margin that decides whether a stressed seedling holds on.

That early advantage carried through to harvest. In the drip lot at two months the treated plants stood about 35 cm taller than the control on average, with visibly more leaf and larger leaves, and they matured faster. At fruiting they set 42.6 pods per plant against 36.2, an 18% increase, on the same nutrient program.

The soil lot answers the question growers actually ask, which is whether one Trichoderma product is the same as another. It is not. Against a leading commercial Trichoderma product grown in the same soil on the same nutrient base, Multi-Tricho finished 7 cm taller, and 20 cm taller than the untreated control, with the largest leaf area and mass in the lot. The benchmark did beat the untreated control. It just did not match a three-species blend.

What the trial does not have is replication statistics or a named laboratory, and the three lots ran as separate tests rather than one design. Read it as three consistent results pointing the same direction rather than as a single statistically powered study.