For example, areas with highly moistened, peaty and saline soils are unsuitable for planting garden crops. Trees develop poorly on heavy clay soils. Groundwater on the plot of the future garden should be no closer than 2–2.5 m to the soil surface. When choosing the plot on which the garden crops are supposed to be grown, indirect factors such as the presence of certain forest species nearby should be taken into account. For example, oak, maple, ash, linden, bird cherry indicate favorable soil conditions, and birch, aspen, pine, spruce signal less favorable soils.
Unfortunately, the future gardener, as a rule, does not have the opportunity to purchase a plot where he would like. Therefore, before laying the garden and during its further operation, soil-improving measures should be taken.
In garden and household plots, a variety of garden, decorative and forest plants usually grow. Each of them has its own characteristics of the growth of the terrestrial part and roots, consumes certain nutrients, releases specific substances into the soil and through the leaves into the air, which have different effects on nearby crops. There are plants that inhibit neighboring crops, which as a result develop worse and bear poor fruit. At the meeting, the roots of incompatible cultures tend to disperse into unoccupied layers of soil.
Scientists have identified certain properties of garden plants that positively or negatively affect each other.