All agricultural producers are fighting for high crop yields. To improve them, scientists and farms are constantly looking for optimal tillage, fertilizers, etc. Biofertilizers, containing so-called effective microorganisms, are more and more often used to ensure optimal plant nutrition. Many scientists have proven and described their positive effect subject to the use of a particular tillage and with which chemical fertilizers their effect is considered to be the best. To obtain high yields, it is also important to take into account the biometric indicators of plants. This article presents a study on determining the height and diameter of the corn stalk, as well as the height of attachment of the first completed cob. Therefore, in a three-factor experiment, we studied the effect of reversible (plowing to a depth of 25–28 cm) and irreversible types of tillage (subsurface cultivator to a depth of 25–28 cm and disking to a depth of 15–18 and 5–8 cm), as well as the effect of such soil probiotics as LEANUM and VITAMIN O7 (used before sowing and on the leaf) on medium-early and medium-ripened hybrids. It was found that all the studied biometric parameters of both hybrids in 2020–2022 were best affected by flat-cutting cultivation to a depth of 25–28 cm. Soil probiotics significantly affected plant height, mainly when applied by leaf. The height of attachment of the first cob for both hybrids was significantly affected by pre-sowing inoculation with both biofertilizers, as well as foliar dressing with LEANUM once and twice.