Tuesday, September 11, 2012

Thriving Houseplants

Hello again,

The following post by Melissa Madigan of Skillin's Falmouth is an excellent primer on how to care for your houseplants in the transitional season of fall. This post will be used as the basis for our upcoming Thriving Houseplants class to be held on Saturday, September 22 at all Skillin's locations:

Brunswick 10 AM, Cumberland 10 AM and Falmouth 10 AM and 2 PM. (The Falmouth 10 AM class is sold out)

Contact us at skillins@maine.rr.com about signing up for this class!

Fall is here and it’s time to bring our houseplants in for the winter, so lets do a health check on them.

How are they doing? Is there leaf drop, yellowing of leaves, bugs? How’s the watering going? Have you treated them with systemic insect control before bringing then back into the house?

When caring for our plants thru the fall and winter there are a few things we need to keep in mind.

When you place your plant in the home you need to take into consideration  the following: 

                   1- window location - N,S,E,W
                   2- window treatment - curtain, insulated, sheer, open, shut...
                   3- is there an overhang? Large trees near by?
                   4- plant location in relation to the window - below the sill, in the window, beside the window, a few feet away from the window....
                   5- how much sun is it getting and for how long?

Signs of light underexposure:
          When plants look spindly, long and lanky, it is usually an indication that they are not getting enough light. Try trimming the plant a bit - it will make it become fuller and place it in an area with more light. 

            It is good to know your plants temperature requirements - most plants do not like it below 58ยบ F. Watch for cold drafts from windows and doors, and keep plants from touching cold windows. 

By the same token do not put them too near a heat source - esp. a wood stove. Do not allow heat to blow directly on the plant as it will cause plant cell damage.

TIP: If your house is usually pretty chilly then  place your plants on a heat mat (like the ones you would use for starting seeds). Plants whose roots are warm can withstand 10 to 20 degree cooler air temperatures.

Watering requirements will probably change as the days get colder, so you should observe your plants and check for their need of water before giving them a drink, not every plant will react the same way to the changes in environment and temperature. You may find mold growing on the sill because the plant may be staying too wet. You may see gnats flying around because they are attracted to the wet soil. Once you dry out the soil both those problems should go away.
Your best bet is to follow the 4 rules of

            Rule #1 - Water regularly - it is imperative that potting soil not go completely dry at any point in a plants life cycle. Allowing your soil to get bone dry increases the odds of soil compaction, thereby reducing the odds of water retention.To avoid this you should check you plants for water every other day - you can do this simply by inserting your finger into the pot. The soil should feel moist (not overly wet) about 2 inches down.
            Rule #2 - Timing is everything! Plants’ watering needs will change with the seasons so there is no steadfast rule on how often you should be watering. Seasons will often dictate your approach - plants will need more water in summer (when it is hot and soil dries out faster) than in fall and winter (when the days are shorter and cool). What kind of heat and how warm you keep your house will also affect your watering schedule.
            Rule #3 - Water Deeply - be sure to add enough water so that some water seeps out of the drainage holes. This will ensure a full watering so that roots in the bottom of the container can take up water. This is not to say you should allow your plants to sit in water for more than 30 mins! Toss out the remaining water in the catch tray.
            Rule #4 - DO NOT OVERWATER! - overwatering plants water logs the soil and prohibits oxygen from flowing freely to the roots of plants. Plants need oxygen to survive. In a short period of time water logging leads to decay and rot. Not good. To ensure that you do not overwater your plants check for dryness first. You also need to make sure your plant has proper drainage and that water can flow thru the container. 

And remember plants dry out much more slowly in cooler temperatures.

TIP: if your plants have do a LOT of growing over the summer and are very rootbound repot it just before you are going to bring it in for the fall/winter - if there is still room for the roots keep them as is in their smaller pots (now is not the time to repot) they are getting ready for winter and are no longer being stimulated by heat and sun to grow - they are simply just sitting tight to get thru the winter (much like we do!)

When overwatered, plants will look like this:
            Leaves will loose their glossy sheen or become light green or yellow in color
            The plant may wilt and the soil may have a foul odor. Root rot, mold on soil                   and leaf drop are indicators of overwatering.
            The solution is to:
            Discard any mushy roots or wilted leaves and repot the plant using fresh potting soil. Remove any excess water in the pot’s saucer. If the plant is very large, use a turkey baster to remove the water.

When under watered, plants will look like this:
            Leaves tend to be small and pale in color, fall off or are wilted. The entire plant may be stunted. Sides of leaves or tips may dry and get brittle. Check to see if it is pot bound. (when removed from the pot you see lots of roots and little soil)

       The solution is to:
            Submerge the complete plant in lukewarm water and let it absorb water, usually for 15-30 minutes. Or water diligently so that the soil in the pot becomes moist throughout the pot.

Signs a plant needs repotting: 
            1- dries out fast
            2- all the water runs thru it when watering
            3- new growth is small

BUT - you should always take the plant out of its pot and give a visual on the roots as the following could also cause the above:
            1- the plant got too dry and the soil pulled away from the side of the pot
            2- the plant hasn’t had a deep drink or thorough watering in a long time

Rules of Repotting
Pot size:
        Never put a plant in too large a container! The new pot should have a diameter and depth no more than 2 inches greater than the old pot. In an oversize pot, the ratio of soil to roots will be too great for the roots to absorb overabundant moister held in the soil (this is also known as pot shock). The resultant root rot can be a serious threat to the health of the plant. If you want to move a newly purchased plant to a  different container, choose a pot of the same size or only slightly larger.

          Always plant into clean containers. You can wash previously used pots in soapy water with a bit of bleach added; soak them for an hour do so, scrub, and rinse well to remove any soap film. You may need to work on clay pots with a stiff-bristled brush or plastic scrubber to remove built-up salt residues from fertilizers and minerals in water.

          Containers with a drain hole in the bottom are generally the best to use, because good drainage forestalls root rot. It’s not necessary to place a broken shard in the bottom of the pot, but if it’s your habit to do so, there’s no harm in it. It is harmful however, to line the bottom of your pots with a layer of gravel. This takes up precious root space and in fact slows down drainage by forcing the soil to hold water longer.

          Water the root ball and the soil mix at least an hour before you begin. While they drain, soak any clay pots you’ll be using in a tub of water. Dry porous containers draw moisture away from the soil at an unpredictable rate; presoaking them retards this water loss. Moisten your new soil mix if it’s too dry.
Feeding your plants - generally you will back off feeding your houseplants in the late fall and winter as most plants enter their dormant period at this time. There are however a few exceptions to that rule. Plants like the Christmas cactus, Poinsettia, Cyclamen, and Primrose to name a few will be entering their bloom period and will need plenty of food to maintain their blooms. 

            Nitrogen - as a rule, leafy green growth is supported by nitrogen (N). All plants need this. Nitrogen should be added to plant pots every six to eight weeks. This can be done in a number do ways: Bat Guano - this potent fertilizer also has a fair amount of phosphorus making it a good choice for fruiting plants.
 Fish meal - is made up of ground-up fish and smells fishy! It will release slowly into you plants and is great for potted houseplants, herbs and veggies! 

            Phosphorus (P) - promotes healthy fruiting and flowering plants. Some good sources of Phosphorus: Bone Meal or Fish Bone Meal - a by-product from a slaughterhouse or fish bones. Bones have a high calcium content, and some nitrogen as well.

            Potassium (K) - encourages strong plant growth. When plants lack potassium, photosynthesis slows down and may weaken the stems. An easy source of potassium is kelp meal (dried and ground up seaweed - can be found in fertilizer such as Neputne’s Fish and Seaweed Emulsion.

Thanks to Melissa Madigan!

Mike Skillin
Skillin's Greenhouses
September 11, 2012

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