Plants have needs too !
Plants have basic needs which if not met will launch a system wide collapse of all metabolic processes leading to death. I know - its sound very dramatic - but its just the way it!
The following are the needs you MUST assure are being supplied at all times. Some of them you may not be familiar with.
Light Intensity
Plants produce sugar in direct relationship to the # of photons their leaves receive. We call this number foot candles. The length of the day also affects how much energy they receive. But most people don't talk photons or foot candles ! We use other words like FULL SUN, PARTIAL SUN, AND SHADE.
FULL SUN means the plant requires 6-8 hrs MINIMUM of solar rays striking their leaves. 4000 – 8000 fc.
PARTIAL SUN plants can manage with 2-4 hrs. MINIMUM of solar rays striking their leaves. 2000 – 4000 fc.
SHADE plants can make sugar with diffused light - without having solar rays directly striking their leaves at all. 1000 – 2000 fc.
NOTHING usually survives long term under 1000 fc. - but there a re a few exceptions !
sitting in dappled sunlight is great sun relief - as long as the birch leaves above are in full sun !
Daylength
Most plants require 12-16 hrs of light per day - depending on where they are located on the planet and the current season. The length of the day actually controls the production of several hormones and substances in the leaves. These regulate growth, blooming and fall leaf drop.
Light Tolerance
The different designations of light play with the issues of required vs tolerance.
Some plants REQUIRE to be in their designation with no exceptions. Some plants can TOLERATE deviations from these conditions and are able to use higher or lower parts of the range. In other words – they are more adaptive. Some can even adapt to the conditions of another designated level all together.
Needled evergreens in general are INTOLERANT to anything but full sun. Placing them in anything lower is usually a death sentence. Broadleaf evergreen plants like boxwood, will tolerate a lower light designation but will get thin and cant be used as a hedge plant. Hosta which prefer shade will burn if placed in a full sun location.
Arborvitae prefer a full sun spot
Water and Soil Oxygen
Water is an essential element of the metabolism of plants including photosynthesis. Without it the systems collapse. Plants need to have this water available in the soil for when they need it.
However, the delivery of water is also important because of its effect on soil oxygen levels. When one waters, the water molecules push the air out of the soil. Water molecules cling to particles of soil and occupy the air spaces between these soil particles. Once the water is either used or drains away, the air containing the oxygen return to the air spaces in the soil.
Roots need this oxygen to survive. In general, when you water too frequently, the air spaces never get replenished with air and the roots die from lack of oxygen.
The time it takes to replenish the air back into the soil will depend on the type of plant, its size, its age, its growing situation, the temperature, the ventilation, season, its blooming cycle, soil compaction, soil texture - lots of things…
a rooftop garden with automatic irrigation
Soil Volume
The canopy of a plant grows in direct relation to the amount of new roots it produces. A growth hormone manufactured in new roots is the reason why. When the soil volume is totally consumed the root system stops producing new roots. As a consequence, the canopy stops growing.
In severe stages, this will affect blooming, water absorption, nutrition absorption, ability to handle the extremes of heat or cold and the ability to ward off diseases and pests. This is commonly referred to as being root bound.
The removal and replacement of soil and roots in the soil mass is the only solution to this problem. Soil replacements should be scheduled at least yearly and twice yearly for fast growing trees. It is required for any plant when the soil volume is less than the theoretical maximum for that plant – what we call soil volume deficiency.
in ground gardens have little to no root bound issues
Soil Acidity
The acidity or alkalinity of the soil refers to the number of free h+ atoms in the soil. This is directly related to the amount of dilute sulfuric acid in the soil. This sulfuric acid comes as a by product of sulfur loving bacteria (thiobacteria) in the soil which consume the sulfur as an energy source, and excrete sulfuric acid. Yes - you read that !
Plants have adapted to soils that contain a lot of sulfuric acid to those that contain none. It is how we classify them as ACID, NEUTRAL or ALKALINE loving plants. The acidity or alkalinity of the soil determines which minerals are released and freed into the soil for the plant to uptake.
Minerals are ONLY released if the pH is at the appropriate level for that mineral. It is essential therefore to test the soil at least once a year and determine the pH and thus the proper level of fertilizers for that plant.
Although hard to tell from just looking at the soil - in general, wet dark soils have a tendency to be acidic. Irrigated soils tend to be leached or washed of sulfur and thus become alkaline. A huge problem using automatic irrigation systems. In ground, the sulfur never really gets leached.
boxwoods like neutral to alkaline soil
Minerals and Timing
Plants require three basic minerals for their metabolic operations. Most of our fertilizers provide these. However, it is the timely application of fertilizers in relation to the season and species that is most important. Applying fertilizers after the period of uptake is useless.
Because different species require different types of fertilizers or combinations of fertilizers throughout the year, it is best to consult your garden calendar for specifics. Or speak to your Plant Specialists gardener !
annuals like lantana should be fertilized constantly during the summer
For a review of your gardens' needs - Call Plant Specialists TODAY !
Don't delay – the sooner the better !
GREENING NEW YORK FOR OVER 52 YEARS !
Article written by our Staff Horticulturist, Peter B Morris, BSc, MSc, MBA
All photographs used with permission from our own customers gardens !