Imporant to avoid too wet confitions, to keep an eye on the light intensity and temperature and to make sure seeds are placed at the right depth. If the tomato seed is placed too deep, the seedling will have to work harder to reach the surface of the substrate. That way it looses the food until it germinates to the outside. If it’s placed too shallow, it will get weak because the roots won’t have proper support.
Cover the seeds lightly with a fitting cover layer. The cover layer should not be wet. Apply the layer by sprinkling the dry material directly over the seeds, following the seeding depth calculation as shown in the infographic above. Sprinkle it loosly over the tray and brush off any excess. Next, lightly spray a little water over the layer. This top layer prevents the seed from drying out and absorbs water from the plug.
- Air humidity: 80-90%
- Temperature: at least 5-6°C lower than in the greenhouse/nursery.
- Moderately moist substrate: irrigation after sowing is sufficient. Moisture level should be 60-65%.
- Time period: Place seed trays in Germination Room immediately after sowing. Leave them there for up to 48 hours (depending on the variety).
Mold is usually created by the growth of filamentous fungi. If the water content is high, these organisms will grow on almost any type of organic matter. While the sight of mold growing on a freshly opened substrate bale may seem worrisome, they are not pathogenic to plants. There are numerous species of fungi, and those found in peat moss are mostly saprophytes, meaning that they only feed on decomposing organic matter. Some of these microorganisms can even have beneficial effects on plant growth.
In unused peat-based growing media that have been stored for a prolonged period, some mold may be seen on the external layer of the mix, just beneath the plastic bag or wrapping. Water can build up in this area of the bale, which generates optimal conditions for fungus development. Mixes with high fertilizer charges or those that are exposed to high temperatures during storage are more at risk to develop mold, but it can occur on almost any peat-based product.
The white mould is Trichoderma. It is a naturally occurring beneficial micro-organism that lives in most soils. Usually you cannot see its presence, but sometimes it appears as white mould on the surface of peat.
Trichoderma is a group of saprophytic fungi, which inhibits the growth of plant pathogenic fungi. It is also used as a commercial biofungicide as it prevents the attacks from plant pathogenic micro-organisms during cultivation. Trichoderma is, therefore, extremely beneficial fungi which naturally protects the substrate from plant pathogens and causes no negative effect to plants.
Yellow or orange powdery like growth on the surface of peat is due toPeziza ostracoderma, commonly called as cinnamon or peat mould. It is another non-harmful but common saprophytic fungi found on peat. Saprophytic fungi live on other fungi in decaying organic material such as peat. They do not live on living plants.
Due to low pH and low oxygen levels that are natural to bogs, plant pathogenic micro-organisms are not present in quality raw material. They have never occurred in analyses. There is no need to sterilise the peat. Heating would kill the beneficial Trichoderma, and on the other hand, sterile growing media would attract harmful fungi and enhance their growth as there would be no micro-organisms, such as Trichoderma, fighting them off.
Sphagnum peat moss contains numerous microorganisms that occur naturally in peat bogs, including the bacteria Bacillus, the actinobacteria Streptomyces, the fungi Penicillium, Trichoderma and Mucor, to name a few. The presence of a healthy community of microorganisms in sphagnum peat moss makes it more difficult for root rot organisms like Fusarium to establish, because the inoffensive saprophytes compete with the pathogens for available resources. Moreover, some species such as Trichoderma and Streptomyces are known to synthetize molecules that are quite effective at suppressing some root rot pathogens though various modes of action.
The microorganism population in peat varies depending on several factors, including the harvesting site. Blond, high quality and less decomposed peat typically has a more diverse and healthy population. It is therefore more susceptible to provide disease suppression.
The mold that can be seen on received picture is caused by saprophyte fungi, microscopic organisms found in peat bogs that are not pathogenic to plants. They mainly develop on the external layer of peat or growing media, underneath the plastic bag or wrapping, where water tends to accumulate during prolonged storage periods, like it was in container for 2 months.
If you receive a product that has visible mold growing on its surface when you remove the plastic bag or wrapping, do not be alarmed. The product is perfectly safe to use and plant growth will not be affected by these microorganisms. The material can be managed like any other peat moss product you have received:
- loosen the substrate and mix thoroughly, this will cause the fungus to collapse.
- add the recommended water to optimize the characteristics of the mix before potting.
- because fungal growth requires nutrients, the occurrence of saprophytic fungi may result in deficiency of plant available nutrients, nitrogen (N) in particular. Use fertiliser from the very beginning of growing to prevent any deficiencies.
Note that the peat is safe to use – the fungi is not harmful to plants. The adverse effect of saprophytic fungi is purely visual. Moreover, there is no effective fungicide available against them. In dryer conditions the fungus will not become visible, so it shouldn’t reappear during cultivation. To avoid all types of fungi during cultivation, allow the surface of the substrate to dry regularly and reduce relative humidity when possible.
Humic substances are the components of humus and as such are high molecular weight compounds that together form the brown to black hydrophilic, molecularly flexible, polyelectrolytes called humus. Many of the components of humus are heterogenous, relatively large stable organic complexes. They function to give the soil structure, porosity, water holding capacity, cation and anion exchange, and are involved in the chelation of mineral elements. The elemental analysis of humic substances reveals that they are primarily composed of carbon, oxygen, hydrogen, nitrogen, and sulfur in complex carbon chains
Humus is defined as a brown to black complex variable of carbon containing compounds not recognized under a light microscope as possessing cellular organization in the form of plant and animal bodies. Humus is separated from the non humic substances such as carbohydrates (a major fraction of soil carbon), fats, waxes, alkanes, peptides, amino acids, proteins, lipids and organic acids by the fact that distinct chemical formulae can be written for these non humic substances. Most small molecules of non humic substances are rapidly degraded by microorganisms within the soil. In contrast soil humus is slow to decompose (degrade) under natural soil conditions. When in combination with soil minerals soil humus can persist in the soil for several hundred years. Humus is the major soil organic matter component, making up 65% to 75% of the total. Humus assumes an important role as a fertility component of all soils, far in excess of the percentage contribution it makes to the total soil mass.
Organic matter is defined as a grouping of carbon containing compounds which have originated from living beings and deposited on or within the earth’s structural components. Soil organic matter includes the remains of all plant and animal bodies which have fallen on the earth’s surface or purposely applied by man in the form of organically synthesized pesticides. A fertile soil should contain from 2 8 percent organic matter, most soils contain less than 2%. In acid, leached soils, which are often sandy, substantial portions of the organic matter is in the form of plant debris and fulvic acids (FAs). In neutral and alkaline soils a large percentage of the organic matter is present in the form of humic acids (HAs) and humin
Humins are that fraction of humic substances which are not soluble in alkali (high pH) and am not soluble in acid (low pH). Humins are not soluble in water at any pH. Humin complexes are considered macro organic (very large) substances because their molecular weights (MW) range from approximately 100,000 to 10,000,000. In comparison the molecular weights of carbohydrates (complex sugars) range from approximately 500 to 100,000. Humins present within the soil is the most resistant to decomposition (slow to breakdown) of all the humic substances. Some of the main functions of humins within the soil are to improve the soil’s water holding capacity, to improve soil structure, to maintain soil stability, to function as an cation exchange system, and to generally improve soil fertility. Because of these important functions humin Is a key component of fertile soils.
Humic acids (HAs) comprise a mixture of weak aliphatic (carbon chains) and aromatic (carbon rings) organic acids which are not soluble in water under acid conditions but are soluble in water under alkaline conditions. Humic acids consist of that fraction of humic substances that are precipitated from aqueous solution when the pH is decreased below 2. Humic acids (HAs) are termed polydisperse because of their variable chemical features. From a three dimensional aspect these complex carbon containing compounds are considered to be flexible linear polymers that exist as random coils with cross linked bonds. On average 35% of the humic acid (HA) molecules are aromatic (carbon rings), while the remaining components are in the form of aliphatic (carbon chains) molecules. The molecular size of humic acids (HAs) range from approximately 10,000 to 100,000. Humic acid (HA) polymers readily bind clay minerals to form stable organic clay complexes. Peripheral pores in the polymer are capable of accommodating (binding) natural and synthetic organic chemicals in a lattice (clathrate) type arrangements. Humic acids (HAs) readily form salts with inorganic trace mineral elements. An analysis of extracts of naturally occurring humic acids (HAs) will reveal the presence of over 60 different mineral elements present. These trace elements are bound to humic add molecules in a form that can be readily utilized by various living organisms. As a result humic acids (HAs) function as important ion exchange and metal complexing (chelating) systems.
Fulvic acids (FAs) are a mixture of weak aliphatic and aromatic organic acids which are soluble in water at all pH conditions (acidic, neutral and alkaline). Their composition and shape is quite variable. The size of fulvic acids (HFs) are smaller than humic adds (HAs), with molecular weights which range from approximately 1,000 to 10,000. Fulvic acids (FAs) have an oxygen content twice that of humic acids (HAs). They have many carboxyl ( COOH) and hydroxyl ( COH) groups, thus fulvic acids (FAs) are much more chemically reactive. The exchange capacity of fulvic acids (FAs) is more than double that of humic acids (HAs). This high exchange capacity is due to the total number of carboxyl ( COOH) groups present. The number of carboxyl groups present in fulvic acids (FAs) ranges from 520 to 1120 cmol (H+)/kg. Fulvic acids collected from many different sources and analyzed, show no evidence of methoxy groups ( CH3) groups, they are low in phenols, and are less aromatic compared to humic acids from the same sources.
Humates are metal (mineral) salts of humic (HAs) or fulvic acids (FAs) Within any humic substance there are a large number of complex humate molecules. The formation of a humate is based on the ability of the carboxyl ( COOH) and hydroxyl ( OH) groups (on the outside of the polymers) to dissociate (expel) the hydrogen ion. Once the hydrogen ions are dissociated a negatively charged anion ( COO- or -CO-) results. Two of these anions can bind to positive metal cations, such as Iron (Fe++), copper (Cu++), zinc (Zn++), calcium (Ca++), manganese (Mg++), and magnesium (Mg++). The simplified reaction ( COO- + Fe++ > > COOFe+ + H) proceeds to bind two anions, frequently a COOH and a COH group. The humate composition of any one humic substance is specific for that substance. Thus there exists a large variability in the molecular composition of different humic substances. Humates from different mineral deposits would be expected to have their own unique features.
Plant grow is influenced indirectly and directly by humic substances. Positive correlations between the humus content of the soil, plant yields and product quality have been published in many different scientific journals. Indirect effects, previously discussed, are those factors which provide energy for the beneficial organisms within the soil, influence the soil’s water holding capacity, influence the soil’s structure, release of plant nutrients from soft minerals, increased availability of trace minerals, and in general improved soil fertility. Direct effects include those changes in plant metabolism that occur following the uptake of organic macromolecules, such as humic acids, fulvic acids. Once these compounds enter plant cells several biochemical changes occur in membranes and various cytoplasmic components of plant cells.
Humic substances have a very pronounced influence on the growth of plant roots. When humic acids (HAs) and/or fulvic acids (FAs) are applied to soil enhancement of root initiation and increased root growth are observed. Thus the common observation that humic acids (HAs) and fulvic adds (FAs) are root simulators.
Humic acids (HAs) and fulvic acids (FAs) are excellent foliar fertilizer carriers and activators. Application of humic acids (HAs) or fulvic acids (FAs) in combination with trace elements and other plant nutrients, as foliar sprays, can improve the growth of plant foliage, roots, and fruits.
Young plant roots, leaves, and growing plants are more responsive to applications of humic substances. Actively growing plant tissues are the most responsive to applications of humic substances. Younger tissues have active transport mechanisms that move the required nutrients to sites of metabolic activity. Side dress applications of commercial liquid humic acids (HAs) and fulvic acids (FAs) to soils during crop production results in direct root uptake.
Humic substances commonly occur within soils waters, compost, peat, and in carbon containing minerals such as brown coals, low grade lignites, and leonardites. Most all soils and waters on the earth surface contain some humic substances in the form of humin, humic acids (HAs), or fulvic acids (FAs).
Humic substances can form naturally within soils properly managed. Certain production practices can help build the humus content of soils. Practices such as crop rotation, using balanced fertilization programs, planting legumes, plowing under green manures, returning organic matter to the land, application of compost, and using minimum tillage practices can all help build humus. An analysis of this situation indicates that the most rapid and practical solution to improving soil fertility is the addition of humates; (mined humic substances) directly to the soil or as foliar fertilizers. In most soils the applications of humate based fertilizers is more important than applying traditional N P K fertilizers. For many years growers have been applying excess N P K fertilizers. Humic substances will maximize the efficient use of residual plant nutrients, reduce fertilizer costs, and help release those plant nutrients presently bound is minerals and salts.