Over Watering your Plumeria

At one time or another we all over water our plumeria or you may live in a heavy rainfall area and had flooding problems. Over watering, prolonged heavy rainfall or flooding can cause havoc on your plumeria. Poor drainage can also contribute to this problem.  

Anaerobic Soil

Over watering your soil causes your soil to be waterlogged, not a healthy environment for plumeria to live. Much like we would not be comfortable living under water all the time.  We need to come up for air and the plumeria roots need oxygen too.  

Saturated soils with poor drainage can quickly become anaerobic, making the plumeria susceptible to diseases like root rot. When plumeria roots sit in excess water for too long, they start to rot or decay. As the roots deteriorate, they can’t take up water, so the plumeria wilts.  

Clues your soil or potting mix needs help

When too much water is around the roots, it is likely the beneficial microorganisms and soil life that were living in your pot and keeping your plumeria healthy have drowned or at best case, their numbers have greatly reduced.  If this is the case, the potting mix or soil may smell ‘sour’ or anaerobic.  Oxygen normally fills the gaps in between the soil crumb structure and all organisms and plumerias need air to live.  When plumeria roots start to decay, you may notice this unpleasant smell. 

If your potted plumeria show these tell-tale signs of over watering, there is a problem with the soil:

  • Your plumeria is wilting, dropping leaves
  • Your plumeria is looking unwell all of a sudden
  • Your plumeria is being attacked by pests or disease
  • Worms are coming up to the surface in great numbers (they are trying to save themselves from drowning)
  • Sometimes you might notice a scum or residue on the surface of the soil  

Here are some suggestions to help you from over watering your plumeria:

  • Adding coarse mulch material to the bottom of the pot will also help drainage
  • Mix your soil with 50% Perlite
  • Use pots with many drain holes
  • Add more drain holes in your pot
  • Locate your pots in well-drained areas
  • Or plant in the ground, when possible  

If the pot or container feels heavy and the plumeria is still wilting, the excess water may not be getting away fast enough.  If you have already drilled enough holes, you may need to actually remove your plumeria from the pot to save it.  Spread out a number of sheets of newspaper in a tray.  Lay the pot on its side and gently slide out the plumeria’s root ball. 

Allow the root ball to dry on the newspapers for about 12 hours or more, then using clean sharp scissors, trim off any dark-colored (brown rather than white) or slimy roots.  When you are finished, re-pot the plumeria in a clean container with some fresh potting mix as already outlined.  

Using Coarse Material in your pot:

We have found that putting an inch of two of coarse, decomposing mulch in the bottom of the pot helps with drainage and plumeria health.  

Most books and websites on container gardening recommend the addition of coarse material such gravel, sand, pebbles, pottery shards or polystyrene pieces to the bottom of pots to improve drainage, scientific studies have consistently demonstrated quite the opposite is true.  According to one scientist, Dr Chalker-Scott, Extension Horticulturalist and Associate Professor at the Washington State University:  

“Nearly 100 years ago, soil scientists demonstrated that water does not move easily from layers of finer textured materials to layers of coarser textured materials.  Since then, similar studies have produced the same results.  The coarser the underlying material, the more difficult it is for the water to move across the material’s face.  Gravitational water will not move from a fine soil texture into a coarser material until the finer soil is saturated.  Since the stated goal for using coarse material in the bottoms of containers is to “keep soil from getting water logged,” it is ironic that adding this material will induce the very state it is intended to prevent.”  

Resist the Urge to Over water:

Resist the urge to water your plumeria without checking to see if they actually need water – it can actually make things worse!  Water logging and compaction can create ideal conditions for diseases such as phytopthora and other fungal attacks.  

Potted plumeria that have been inundated with water will also have likely leached out much of the plumeria food or fertilizer that was in the pot previously.  You will need to replace this food source with some more organic fertilizer to ensure your plumeria has the energy it needs to regain its health.  

If you notice discolored or yellowing leaves, this is often a sign your plumeria is crying out to be fed. This is because it is missing essential minerals!  A slow release, powdered or pelleted fertilizer and compost can help restore the nutrients.

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Hard water and soft water

All over the world, questions pour in as to the distinctions between hard water and soft water and how these differences affect how and what plants are fed.

By Geary Coogler, B.Sc. Horticulture

The U.S. department of the interior and the U.S. Geological Survey (USGS) define 60 mg/l (60 ppm) or less of certain ions as soft water. Water with over 120 mg/l (120 ppm) is considered hard, and water in between is moderately hard. Other countries and agencies hold their own distinctions. (See Table 1) Strictly speaking, it is the concentration of dissolved positive multivalent metallic ions with a charge of +2 or +3, typically Calcium and Magnesium. This effect can be heightened by the presence of dissolved in water, can and will react with other elements added to the water, or with anything it comes into contact with. Hard Water is an issue for cleaning, for equipment, and increases the chemical activity of the water especially where pH is concerned; it is often considered healthier. Typically this comes from ground water that has been exposed for longer periods to mineral bearing rock. Well water is a prime example.

Soft Water on the other hand, allows soap to foam up and work better, has less issues for equipment, and provides more of a blank slate in chemical reactions; studies have shown a correlation between soft water and health issues including cardiac disease. Typically this comes through surface water, rivers, streams, and lakes that have not been exposed to mineral bearing rock formations for long periods. It can also be composed of treated water where most of all ions have been removed or replaced by single valance atoms such as Sodium from water softening equipment.

Table 1.

Recommended upper limits of chemical factors in irrigation water for greenhouse crop production (Based on 1 and 2, see bibliography)

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The values can vary by EC meter. Here we have used the Truncheon Meter to calculate the values.

Problematic ions

Bad Water is bad water, whether because it has a high salt content or has undesired chemicals in it. It can be found anywhere especially in industrial areas, intense agricultural regions, and close to bodies of salt water. This has no bearing on water hardness.

Do not confuse ion or salt concentration with hardness or softness of water. Hardness is a function of multivalent ions like Ca2+ and Mg2+ not monovalent ions like Na+ or Cl+. Monovalent ions also show up in the Total Dissolved Solids (TDS) of a solution, so it is possible to have a TDS of 450 mg/L (1 ppm = 1 mg/L), derived from adding table salt to distilled water, but have soft water. There is no direct correlation between TDS or EC (electrical conductivity) and water hardness unless it is known with certainty that all EC derives exclusively from Ca, Mg or other positive multivalent metallic ions. Sugar water has EC but no hardness. Water softeners work this way by displacing the problem ions Calcium and Magnesium with Sodium ions. The EC stays the same or increases but the water goes from hard to soft; not a good thing for plants.

For us, the big question is “How does this affect the nutrients for plants?” One of the biggest effects for growing systems using hard water is the potential for insoluble deposits of Calcium or Magnesium carbonates. This combining of these ions is an endothermic reaction meaning that as heat is supplied to the solution, the process gets faster. The process of pumping water from a reservoir, through a pump, through smaller pipes, onto a table top and through a root system imparts increasing amounts of heat to the solution so the reaction is natural and persistent.

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The EC value cannot tell you about the quality of your water. Sometimes hard water with an EC of 0.5 may still be high quality water for growing, while other water with the same EC could be bad or even very harmful to your plants because it contains the wrong salts and chemicals.

Reduced flows

At this heat enters the system, the combining of these elements increases, resulting in the deposition of insoluble materials on the inside of pumps, pipes, tubes and medium of the growing system. Ultimately this leads to reduced flows, blocked emitters, burnt out pumps and so on.

The effect on the chemical profile of the nutrient package can also be affected through various antagonistic relationships between individual elements and the overall affect on pH. The harder the water the more Calcium and Magnesium is being applied. The higher these elements get in relation to some other elements like Potassium and Phosphorus, the less available these elements become, effectively locking out these elements. These positive Ions will bring the pH of the solution up, and when hardness is also affected by carbonate levels, the pH effect will continue into the medium to which it is applied. The harder the water, the more acid is required to lower the pH.

There are a couple of commercial solutions to various situations of concentration and hardness. The first is Water Softening. Water softening involves flooding the water with a monovalent ion, typically Sodium, which drives out the Calcium and lowers the hardness of the water. This is great for clothes washing and baths but not so great for consumption by plants and humans, especially where the water is very hard.

The next is Reverse Osmosis (RO), a process where tap water is forced through a series of membranes with progressively smaller pores that block molecules and atoms of a certain size. This filters out the Calcium and other larger elements effectively lowering the water hardness. It also strips out most of all the elements including harmful molecules, Sodium ions, and most other ions thus effectively lowering overall Total Dissolved Solids and EC. It is also expensive to install and maintain and really not always necessary, at least to use pure Reverse Osmosis water.

Water sample

Decent nutrient companies should take the concerns of hard or soft water into account with the design of their products. Different lines have different needs in this area. Most of these differences are influenced by the medium the product is applied to. Potting mixes have a greater buffering capacity, the ability to hold elements, and should not be recirculated. Recirculating adds more heat to the system and allows deposits to form more readily. Potting mixes have natural buffers that hold pH changes down. The difference in content should be adjusted through the correct ratio of nutrients found in a fertilizer specially developed for potting mixes.

Only soft water is recommended for recirculating systems on inert mediums, so pure RO is acceptable in this system. Recirculating systems have to be able to adjust to, not only the hardness of the water, but also to the additional elements applied in the tap water over and above what is added or needed in the nutrient added. Controlling salt composition is critical because this also affects pH and pH is critical in signaling a plant’s flower response (in addition to photoperiod change). The best would be to use a nutrient which is designed to work with tap water EC values no greater than 0.3 – 0.4 mS/ cm while providing some buffering for pH control in the system (for example CANNA AQUA).

Another situation of current growing systems is the Run-To-Waste system where tank mixed nutrients are applied to a plant and the excess is allowed to drain away and not be re-captured. In this system, it is important to not only adjust the pH once it is mixed, but to maintain that pH across time as the product sits in a prepared tank. This keeps pH swings down while keeping insoluble compounds from forming. Also, there are less Calcium and Magnesium ions available in soft water and the amount needs to be augmented or replaced to achieve the correct disposition of ions. To make growing easier while allowing you to worry less about nutrient composition you should use a nutrient brand that has both a soft water and a hard water version (for RTW) to choose from (like CANNA SUBSTRA). How to know when to use the Hard Water version or the Soft Water version? Simple, see the above explanation and run a water sample.

So, what is gained with this knowledge: the appreciation of the fact that there are many aspects affecting water quality. Not only is the total amount of dissolved ions an issue, but also the composition of these elements and the effect they have on added nutrient packages and the post chemical reactions that can and will occur. Ultimately, it all affects the plant. Nutrients have to be designed and used based on the conditions of the water that the grower intends to utilize as source water. In the end, it is also about correctly designed nutrient packages that allow for both the plant’s nutrient requirements and the long term effect on plant development, and the effect of the medium on composition, storage, and reactivity. Testing is knowing, and knowing is growing; how much do you know?

Bibliography

  1. Baily, D, T Bilderback, and D Bir. “Water considerations for container production of plants.” North Carolina State University Horticulture Information Leaflet 557. 1996.
  2. Kessler Jr., J. R. “Water Quality Management for Greenhouse Production.” Alabama Cooperative Extension Service Publication ANR-1158. Alabama A&M and Auburn University, 2005.

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Water types, quality and treatments

Good quality water is the foundation of all soilless growing, however not everyone is blessed with a suitable water source for hydroponics. Even crystal clear water may contain a range of minerals, water treatment chemicals and pathogens which can damage plants and slow growth. Luckily, water is relatively easy to treat and some growers choose to install small reverse osmosis (RO) units just to ensure their water is always top quality.

By Lynette Morgan, Suntec

 

Water types and potential problems

 

Water can be sourced from wells, or collected from roofs, streams, rivers or dams, but many growers are reliant on municipal or city water supplies and while these are usually safe to drink, they can sometimes pose problems for plant growth. The main quality problems encountered with different water types are as follows.

 

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Some water sources can carry plant disease pathogens such as Pythium which cause root browning and death if they take hold of a weakened plant.

 

Ground water (streams, rivers and dams)

 

Ground water sourced from rivers, streams or stored in dams/reservoirs typically poses the most problems for soilless growers, particularly if the water is not treated before use. Water which is continually exposed to air and soil becomes contaminated with organic matter, minerals leach from the surrounding area, and pathogen spore loading can be high. Many greenhouse operations use open air storage dams as an economic method of storing holding large volumes of water collected from greenhouse roofs or other surfaces, however this water is typically filtered and treated before use. River or stream water often has inconsistent water quality as operations being carried out up stream affect composition of the water and rainfall and flow rates also fluctuate throughout the year.

 

Well water

 

Water from wells in different locations around the world can vary considerably in quality. Very deep wells passing through certain soil layers will give an almost `filtered water’ although some minerals are always likely to be present in ground water. Some wells, particularly older types, or those which have been poorly maintained and are shallow can present problems with contamination from pathogens, nematodes and agrichemicals leached through the upper soil layers into the well water2. Well water may be `hard’ and contain levels of dissolved minerals such as calcium and magnesium and other elements depending on the soil type surrounding the well.

 

High levels of sodium and trace elements are the most problematic for hydroponic growers, levels in excess of 2000ppm sodium have been found in inland well waters in some arid regions, although most well waters don’t pose such an extreme problem. Sodium is not taken up by plants to any large extent, hence accumulates in recirculating systems, displacing other elements. Trace elements in ground water, such as copper, boron and zinc may sometimes occur at high levels. Soilless growers utilizing well water are advised to have a complete analysis carried out on their water source to determine if any potential problems exist.

 

Rain water

 

Recirculating systems such as NFT can compound some water problems and unwanted elements such as sodium can accumulate over time.

 

Rain water is generally low in minerals, however acid rain from industrial areas, sodium from coastal sites and high pathogen spore loads from agricultural areas do still occur3. Much of this contamination has been found to happen when rain water falls on roof surfaces and picks up the organic matter, dust and pollutants which naturally collect there. In fact, numerous studies have shown that due to contamination following contact with catchments surfaces, stored rainwater often fails to meet the WHO guideline standards for drinking water especially with respect to microbial contamination3. In the USA, rainwater collected within 48km of urban centres is not recommended for drinking due to atmospheric pollution3. While drinking water standards don’t necessarily apply to hydroponic growing, the fact that high levels of microbial contamination often occur in stored rainwater means that common plant pathogen spores are also likely to be present. Rain water is best collected from clean surfaces with a ‘first flush’ device installed. which allows the first few minutes of rainfall to be discharged from the roof before any is collected for use.

 

Rain water may also contain traces of zinc and lead5 from galvanized roof surfaces or where lead flashings and paint may have been used4 and is a greater problem when the pH of the rain water is low. Generally, rain water collected from greenhouse roofs is free of zinc and lead problems.

 

Hard or soft water

 

‘Hard’ and ‘soft’ are terms used to describe the quality of many water sources. Hard water has a high mineral content, usually originating from magnesium, calcium carbonate, bicarbonate or calcium sulfate, which can cause hard, white lime scale to form on surfaces and growing equipment. Hard water may also have a high alkalinity and a high pH, meaning that considerably more acid is required to lower the pH in the hydroponic system to ideal levels. While hard water sources do contain useful minerals (Ca and Mg), these can upset the balance of the nutrient solution and make other ions less available for plant uptake. Smaller growers can counteract this by making use of one of the many ‘hard water’ nutrient products on the market. Soft water, by comparison, is a low mineral water source. Often rainwater is ‘soft’, while municipal water sources across the country range from very hard to soft, depending on where the individual city water supply is taken from.

 

Other water types

 

Some growers prefer to start with water which has been pre-treated to remove any chemicals, pathogens and other contaminates. RO (reverse osmosis), distilled water, filtered and bottled water are all options for small growing systems and those concerned with water quality.

City and Municipal water quality

Many city water sources are perfectly acceptable for soilless growers and hydroponic systems and can be used with no adjustment or treatment. However, the water treatment options used by city water suppliers change over time and with advancing technology. In the past, the main concern was chlorine in city water supplies. Chlorine is a disinfection agent which destroys bacteria and human pathogens, and residual chlorine can be detected by smell in a water source. High levels of chlorine can be toxic to sensitive plants, however chlorine dissipates rapidly into the air and can easily be removed by aerating the water or just letting the water sit or age for a few days before use.


Solution culture systems don’t have the buffering capacity of those using a soilless substrate so are more prone to problems with water quality.

 

While the chlorination of water supplies was easy to deal with, nowadays, city water treatment plants are moving more towards the use of other methods of treating drinking water. It has been found that some human pathogens were resistant to the action of chlorine, and consequently drinking water regulations were changed and alternative disinfection methods are being used more frequently. These days, water may still be chlorinated, but an increasing number of city water supplies have switched to use of ozone, UV light, chloramines, and chlorine dioxide. While many of these methods present no problem for hydroponics and soilless growers, the use of chloramines and other chemicals by many city water treatment plants can pose a problem for plants where high levels are regularly dosed into water supplies.

 

Chloramines are much more persistent than chlorine and take a lot longer to dissipate from treated water, hence they can build up in hydroponic systems and cause plant damage. Damage to plants caused by chloramines in city water supplies is also very difficult to diagnose as it looks similar to the damage caused by many root rot pathogens and growers are often unaware of what is causing the problem. Some plants are also naturally much more sensitive to chloramines than others, so determining levels of toxicity has also been difficult. One hydroponic research study has estimated that the critical level of chloramines at which lettuce plant growth was significantly inhibited was 0.18 mg Cl/g root fresh weight1.

 

Hydroponic growers who have concerns about the use of chloramines in their city water supply can treat the water with specifically designed activated carbon filters or by using a dechloraminating chemical or water conditioners which are sold by the aquarium trade to treat the water for fish tanks. The chloramine carbon filters must be of the correct type that has a high quality granular activated carbon that allows for the long contact time required for chloramine removal. Growing systems that utilize substrates such as coco are a safer option than soilless culture or recirculating systems where water treatment chemicals are suspected to be a problem. Natural substrates provide a ‘buffering’ capacity in a similar way to soil and can deactivate some of the treatment chemicals contained in the water supply.

 

Other common water quality problems include the use of ‘water softener’ chemical either by city treatment plants, or in the home – these are often sodium salts which result in problematic sodium levels in the hydroponic nutrient. If sodium levels are too high, either through use of water softener chemicals or naturally occurring in the water supply, RO is the best option for sodium sensitive crops.

 

Tips and tricks for growers

 

How do you know if you have a water quality problem?

 

It can be very difficult to determine if a water quality issue is responsible for any plant growth problems which might be occurring. Many diseases and errors with nutrient management or incorrect environmental conditions will produce symptoms very similar to common water quality problems. Ideally, obtaining a full water analysis is useful for most growers, however detecting other issues such as chemical or microbial contamination is more complex. The simplest method of determining if water quality is the cause of growth problems is to run a seedling trial – growing sensitive seedlings such as lettuce using RO or distilled water as the ‘control’ or comparison will usually show up any problems originating from the water supply. Keeping all other factors such as nutrients, temperature and light the same between the plants in the different water samples and using a solution culture system will give the most accurate test. Comparing growth in the pure water to the suspected water sample will reveal any problems (if growth problems appear in both seedling treatment water samples, then something other than water quality is to blame). Water quality problems may show as stunted roots which don’t expand downwards, short, brown roots, yellowing of the new leaves, stunted foliage growth, sunken brown spots on the foliage, leaf burn and even plant death.

 

What to do about suspected microbial contamination

 

Zoosporic pathogenic fungi such as Pythium and bacteria can survive in and be distributed by water6. Water sources which may not have been treated and may contain disease pathogens such as ground, river or steam water can be relatively easily cleaned up by the grower before use. The safest options are UV, ozone and slow sand filtration as these won’t leave chemical residues which may harm young, sensitive root systems. Small UV treatment and filtration systems such as those used in fish ponds and aquariums are suitable for treating water for hydroponic use and will kill plant pathogens and algae. However these are best used for treating water only, not nutrient solutions as UV can make some nutrients unavailable for plant uptake.

 

Even clean, clear water may contain a range of minerals, water treatment chemical and pathogens which can damage plant growth.

 

What to do about other contaminates and treatment chemicals

 

Activated charcoal (slow) filters are still one of the more reliable and inexpensive ways of removing suspected contaminates from a water supply. Herbicides, pesticides, chlorine, chloramines, and other chemicals are reduced to low levels by suitable activated charcoal filters and these can be used by small and large growers alike. If chlorine alone is a problem, aerating the water for 48 hours by using a small air pump will dissipate this chemical. Using substrate-based systems incorporating a media such as coco fibre will give a greater degree of protection and ‘buffering’ capacity where chemical contaminates are suspected.

 


Aeration of chlorinated water supplies will cause the chlorine to dissipate, making the water safe to use in hydroponic systems.

 

What to do about excess minerals

 

Often it is possible to dilute a water supply which may have a slight excess in certain minerals, particularly trace elements, with a higher quality water source, however for water sources with a high natural salinity reverse osmosis or distillation are the only methods of demineralization. Some crops such as tomatoes are far more tolerant of excess minerals and salinity than others such as lettuce, so this factor should be taken into account.

 

What to do about ‘hard’ water with a high pH

 

Hard water is best treated with acid to lower the pH to 6.5 before adding any nutrients to make up the nutrient solution or before using the water to top up a nutrient reservoir. This will reduce the total amount of acid required in the system to keep pH under control. Hard water also contains minerals such as calcium and magnesium, so using a specific ‘hard water’ nutrient formulation or product in recirculating systems is advised, since these will keep nutrient ratios more in balance and also assist with keeping pH in check.

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