When it is necessary to repot?
Repotting of ornamental species is a practise to ensure the right conditions for growth. When the roots have completely occupied the available soil and have started to grow preferentially in the space between pot and soil, it’s the time to choose a larger container and proceed to repot. The transplant should be done annually, if the container is small, up to 16-18 cm in diameter. The replacement can be carried out every two or more years for larger size and/or when plants have slow growth: this is the case, for example, of succulent plants. The operation is not necessary for big plants in pots or boxes of sufficient size to allow the maximum expansion of the roots. In these cases, it is appropriate to renew annually the layer of topsoil.
Which is the best time to perform the transplant?
The best time is spring or late autumn, until the first winter cold. Tropical plants do not have a real period of vegetative stasis, but respond positively to the increase of natural light during spring months. It’s better to not repot when the plant is dormant, because the new volume of growing medium would not be readily explored by new roots, and the consequent stagnation of humidity favor the appearance of roots rot.
Which is the better way to repot?
– Water the plant Two or three days before repotting. This procedure is necessary to prepare the roots to transplant: if the roots are well hydrated will suffer less stress;
– After a few days, remove the plant from the old pot;
– Gently remove the old growing medium, taking care to not break the roots;
– If necessary, with a pair of sharp and clean scissors, cut off parts of damaged or blackened roots;
– At the bottom of the pot, place a layer of expanded clay to protect the drainage holes (at least 3-4 cm);
– Fill the pot with a handful of Growing Medium and lay the plant above;
– Fill with additional Growing Medium, making a slight compression;
– Make a light irrigation.
How to choose the suitable growing medium?
There are many available formulas, some with versatile use, other more specific, requiring the use of selected raw materials for particular purposes. The rules to follow in choosing a right product for cultivation in pots are based on the roots physiology. Plant roots are the engine of growth, because they absorb water and nutrients. To have an efficient absorption, the roots must be able to breathe. Breathing is a physiological process that consumes oxygen and produces carbon dioxide; the opposite of photosynthesis performed by the foliage. Therefore, a suitable growing medium must always have a quote of air available for the roots. To make it possible, the growing medium must have an adequate physical structure (grain size). The bigger the pot we’re going to fill, the greater will be the size of the particulates. For larger pots, we have to prefer fibrous growing media, better if enriched with inert materials (e. Pumice, perlite, etc.). For smaller pots, also growing media with fine particles are suitable.
Which are the preliminary actions that can maximize the performance of the potting soil?
During packaging, a mechanical compression can partially damage the structure of potting soil. In addition, during the pre-employment storage, the potting soil can be dehydrate and consequently become hydrophobic (struggling to absorb the irrigation water). For these reasons, after opening the pack, it is good practice to make an aeration of the product, mixing it by hands. Subsequently, using a nebulizer, you can spray a little water quantity to moisten and prevent any hydrophobia. All these operations can be performed on a normal table opportunely protected by a sheet of paper and do not require that a few minutes.
Can the chemical characteristics of growing medium affect the final result?
The chemical characteristics of the soil are displayed in the packaging label, The values of pH and electrical conductivity, indirect index of the salt content, are of particular interest. Plants physiology is varied and there are plants more or less tolerant of pH and salinity. In particular, high salinity may demage the smooth absorption of water and nutrients. The higher salinity values, are normally found in the family of multi-purpose growimg media, which are designed for different uses and not only for repotting (eg. Planting in the ground, etc.), But is not a always valid rule. Take care to evaluate the hardiness of the plant before you repot, or, when in doubt, choose a specific potting soil. Even acidophilic plants (eg. Azaleas, Camellias, Rhododendrons, heathers, etc.) That need an acidic pH require special attention. Also in this case, it is good to refer to highly specific products.
It ‘good to fertilize after repotting?
All commercially prepared are sufficiently provided with nutrients to support growth of the plants for a few weeks. Additional fertilizer may be deleterious, because it increases the salinity and worsens the absorption. It’s better to avoid fertilization for 3-4 weeks afrer repotting. Only later, when the initial soil nutrient content will be depleted, you can proceed to the fertilization using soluble fertilizers, or granular fertilizer to be spread on the growing medium surface.