Gardening with Gary

Gardening Advice from an Expert

Orchids

Q. What is an appropriate fertilizer for grounded orchids?

A. I assume you mean orchids planted in the ground as opposed to pots. Their needs are the same. This Orchid Lady has the best comprehensive website on their culture. Check the URL below.

When you are fertilizing orchids, you need to remember that most orchids grow above the ground (usually attached to trees) and that they are fed and watered by rain runoff containing very diluted nutrients. Because of their natural habitat, most orchids are not heavy feeders. The old saying, "weakly, weekly" is a good rule of thumb (fertilize using a weak solution one day per week) when fertilizing orchids.

The correct type of fertilizer to use on your orchids is very important! Avoid using general purpose fertilizers designed for lawns and gardens. All fertilizers consist if three main ingredients: Nitrogen--(N)--which promotes general plant growth Phosphorus--(P)--which promotes flowering Potassium--(K)--which promotes strong roots. The ingredients are mixed in various combinations because plants have different needs. The combinations are indicated by a three number code: The first number is the percent of nitrogen (N) The second number is the percent of phosphorus (P) The third number is the percent of potassium (K)

A good balanced fertilizer like 7-9-5 (N-P-K) is good for all mediums you might be using to grow your orchids in. For years, it was thought that bark robbed nitrogen from the orchids and that a high nitrogen fertilizer such as 30-10-10 was needed. However, recent research in this area has proved this to be untrue. To help promote flowering, you can use a special type of fertilizer called "blossom boosters." This is used just prior to bud formation and is a 3-12-6 formula.

Do not use fertilizer containing urea on any orchid. Urea requires breakdown by soil microbes. A toxic salt build up can occur that can burn tender roots. You may notice that when the three numbers are added up, they don't total 100%. The missing percentage is composed of inert ingredients. Fertilizers are distributed in many forms, granules, liquid, spikes, etc. I recommend you use a water soluble (granules that are dissolved in water or liquids that are diluted with water prior to use) type orchid fertilizer which should be available in most garden centers.

The recommended dosage varies according to the manufacturer but is usually only 1/4 or 1/2 teaspoon per gallon of water. Follow the manufacturer's directions and remember, "weakly" is better! Less is better than more!

Some orchidists recommend fertilizing every week and others recommend every other week. I personally water every week and add fertilizer to my water every other week.

Smaller than normal growth or yellowish leaves is an indication of possible insufficient fertilizer. Most of the media used to pot orchids offer no nutrition to the plant. Organic media (bark and moss) will release small amounts of nutrients as they decompose.

A salt buildup (which looks like white crusts on the media and around the pot) is a sign of over feeding. The roots of your orchid will turn black if they come into contact with this salt buildup and if the buildup continues, the plant could die. When the tips of the leaves die, it could also be an indication of too much fertilizer.

To prevent this condition, you should practice an alternating watering and fertilizing routine. Give fertilizer to your orchid at every other watering. This will allow the fresh water to flush your orchid of any leftover fertilizer, salts, and minerals that may have built up in the pot.

The best thing to do is to repot your orchid in a new pot with new media. Before placing your orchid into its new pot, flush the salt from the roots and around the growths with running water. Reduce the amount of fertilizer to the recommenced amounts.

Water your orchid with fresh lukewarm water (NEVER cold water) weekly. Add fertilizer to the water every other week. If the tips of your plants become dry and start to turn black, it could be a sign of over fertilizing. Be sure you are flushing the excess fertilizer out of your media between feedings. Don't fertilize a sick plant. Don't add extra fertilizer to your plants to help them grow. This will not help. Make sure your water is lukewarm, don't use cold water. Pour the fertilizer thru the pot or over the media just like you were watering. Do not catch the fertilizer runoff and then use it on another plant. This practice will spread diseases. Learn what kind of an orchid you have. Some have "rest periods" and do not require feeding during this time.

From: Linda's Orchid Page http://www.orchidlady.com/index.html#top

Q. I have had an orchid plant for approx. 6 years. It produced 1 small purple bloom about 8 months ago. Now it has a stem with several buds on it. The problem is that the buds dry up and fall off before ever opening. What can I do?

A. This sounds to me like an orchid grown indoors without enough humidity. They drop flower buds prematurely if the plant is stressed by water: either from the top, meaning the root ball dries out due to lack of watering, or from the air, meaning that the relative humidity around the plant is low.

Place the plant on a large enough saucer with an inch of pebbles underneath the pot. Keep water in the saucer up to the bottom of the pot, making sure that the pot is not down in the water. This would cut off air to the roots and lead to death.

Mist the plant regularly, especially when the air is dry, when you have a heater going or the air is dry due to a draft or warm or hot, windy days outside. Mist early in the AM and again later on, but not near dusk, as you do not want wet foliage as the temperature drops.

Make sure that you are fertilizing with an orchid food. Read the label for dosage and frequency. Without food, orchids do not do very well.

Repotting orchids disturbs their flowering. They wait until root bound to bloom, so it you repot, you will suffer no blossoms for several years. But, they must be repotted from time to time, when the roots have overgrown the pot and you need to repot to a larger size. Check the rootball to see if you have circling roots round and around. If you do, you will need to slice them at parts around the ball and pot into new soil mix in a larger pot.

DJ writes~
I have a double spike Cymbidium standing approx. 36" tall. New shoots are coming up in it and it just stopped blooming. How do I care for it now?

A. Klehm Growers are renown orchid growers and have a wonderful write-up on the care as follows:

Cymbidium [sym-BID-ee-um]

These Orchids are prized for their long-lasting sprays of flowers, used especially as cut flowers or for corsages in the spring. There are two main types of Cymbidium -- standards and miniatures. Where summer nights are warm (above 70 F), only miniatures can be recommended, because many are more tolerant of heat and able to flower in warmer weather.

Light is important for growing Cymbidium. Coming from cool and bright areas in Asia, they need high summer temperatures, especially at night, may prevent the plants from blooming. The maximum amount of light possible, short of burning, should be given to plants. This means only light shade during the middle of the day, or about 20 percent shade. In cool areas (such as coastal California), full sun is tolerated. Leaves should be a medium to golden green in color, not dark green.

Temperatures are another critical factor in flowering standard and miniature Cymbidium. During the summer, standard Cymbidium are usually grown outside in semishade, where day temperatures should be 75 to 85 F (or more), but night temperatures in the late summer to autumn (August to October) must be 50 to 60 F to initiate flower spikes. Optimum temperatures in winter are 45 to 55 F at night and 65 to 75 F during the day. When plants are in bud, temperatures must be as constant as possible, between 55 and 75 degrees F. Miniatures can stand temperatures five to 10 degrees higher than standards and still flower. Most Cymbidium can tolerate light frosts and survive, but this is not recommended. Bring them inside when temperatures dip to 40 F. In mild climates, they can be grown outside year round. A bright and cool location inside is best for winter months.

Water to provide a constant supply of moisture to Cymbidium, which are semi-terrestrial plants. They generally produce all vegetative growth during the spring and summer and need the most water during that period. Water heavily during the growth season, keeping the potting material evenly moist. Reduce water when the pseudobulbs complete growing in late summer. Keep barely moist during the winter.

Humidity outdoors is usually sufficient during the summer, except in dry climates, where evaporative cooling in a greenhouse is necessary. Keep humidity at 40 to 60 percent during the winter, especially if plants are in bud. Keep the air moving to prevent fungus (Botrytis) from spotting the flower.

Fertilize at the proper time to help Cymbidium flower. During the growth season (spring through late summer), high nitrogen fertilizer (such as 30-10-10) is used. In late summer, use a high-phosphorus, blossom-booster fertilizer (such as 10-30-20), to help form bloom spikes. Fertilize at full strength every week to two weeks. In winter, fertilize once a month.

Potting is usually done in the spring after flowering, usually every two years or when the potting medium decomposes. Shake all of the old potting mix off the roots, dividing the plant if desired. Pick a water-retentive potting mix; medium-grade fir bark with peat moss and perlite is a common mix. Select a pot that will allow for at least two to three years of pseudobulb growth before crowding the pot, while planning on placing the active growing pseudobulb(s) of the division farthest from the side of the pot. Spread the roots over a cone of mix in the bottom of the pot and fill the container with medium, working it among the roots, tamping firmly. Single backbulbs need not even be placed in mix until new growth and roots are noted. Keep shaded and warm until new growth sprouts, and pot as above.

http://www.klehmgrowers.com