Soil: THE IDEAL SOIL FOR CALADIUMS
- I am going to dig out my old flower beds and replace them with new soil before I plant my caladiums. What would be the ideal soil to use?
Answer: Caladiums are not too specific about the soil type that they will grow in, as we plant them in a high organic muck soil in the fields when they are being propagated. Some people use straight peat moss when they grow them in pots. What you need is a high organic soil that has both good moisture holding capacity, as well as good drainage. For the garden, I would use about 50% peat, 30% composted bark or vermiculite, and about 20% sand. Try to adjust the pH to 5.5 to 6.0. With this said, caladiums will grow in any soil type: clay, sand, etc.
Soil: BLACK WALNUT TREES AND CALADIUMS
- I have a lot of Black Walnut trees around the house and plants have a difficult time growing under them. Will caladiums be a possible choice of plants?
Answer: As you are probably aware, black walnut trees exude a toxin that tends to inhibit the growth of most plants in their proximity. I would guess that caladiums would not do well if the tubers are planted in the ground close to the tree roots. But there is a solution to that: just plant the tubers in containers that contain a potting mix that you can buy from your local garden supply store. Make sure the soil has a high organic (peat moss) content that will hold moisture and has a pH of 5.0-6.5. You can mix a slow release fertilizer in the soil before you plant. I would use three #1 or one jumbo tuber per six-inch pot. Cover the caladium tubers with at least three inches of soil. Bury the pots around the tree up to the lip of the pot and then cover the area with some type of organic mulch about two inches deep. Water the caladium plants regularly, stand back and watch them grow!
Fertilizing: HOW TO FERTILIZE CALADIUM PLANTS
- My caladiums are really growing fast, and I am afraid that they will run out of fertilizer. What do I use and how much?
Answer: In general, caladiums are not "heavy feeders" and require only a moderate amount of fertilizer. Your soil type and temperature will also affect the amount of fertilizer you need. Over feeding your caladiums can cause the leaves to turn green and possibly get holes in them.
Caladium plants grown in sandy soils and with higher temperatures will require more fertilizer than those grown in organic soils and at cooler temperatures. As a general rule of thumb, use between 1 and 1.5 pounds of a 8-8-8 or 10-10-10 fertilizer per 100 square feet of planted area. You could apply this amount every 5 to 6 weeks. If you live in a hot rainy location with sandy soils, you will need to increase the frequency. If you like to use a liquid feed program, use a 500 ppm Nitrogen solution of a 20-20-20 about every 2 weeks. In Florida if we get 1.5 inches of rain on our sandy soils, all the Nitrogen and Potassium will be gone so we need to apply more fertilizer. In organic soils, it doesn't leach out as badly. Remember that use of too much fertilizer is not good for the environment. It is always better to use less fertilizer and make more applications.
Fertilizing: BULB BOOSTER, MANURE, SOAKING CALADIUMS
- Would it be okay to use Bulb Booster in the planting hole when planting caladiums? Also, would soaking the tubers in a liquid kelp solution prior to planting help the plants grow?
Answer: The major ingredients in any type of pre-planting fertilizer or growth enhancer are generally potassium, phosphorus, and some hormones that promote root growth. Any help that you can give to the plants to get them started will be beneficial; just don’t overdo the amount that you put in the hole. Remember that roots of caladiums develop on the top of the tubers, so don’t cover the tubers with anything but good soil that has low soluble salts. Also, never fertilize caladiums, either in the planting hole or in the beds with manure. The ammoniacal form of nitrogen that results from the degradation of manure can increase the sensitivity of the plants to certain soil diseases, such as Fusarium. Kelp solutions have been promoted for years as a growth enhancer, as kelp contains most of the base elements needed for plant growth, many vitamins (most of which are better for people than plants), and some growth regulators that enhance rooting and the uptake of nutrients. You certainly will not harm the caladium plants and the added nutrients could increase plant growth. Just use a low concentration so as to not damage the developing caladium leaves and roots.
Growing Indoors: GROWING CALADIUMS INDOORS IN WINTER
- Can I grow caladiums indoors in the winter for a bit of color?
Answer: Caladiums naturally go dormant in the winter. They need this dormancy just like they need a growing season each year. For this reason, winter is not the time to grow them indoors. However, in summer months caladiums do well when grown in containers indoors, especially if you can give them some supplementary light and keep them warm (above 70°F). Since many of the Fancy Leaved cultivars get very tall and stretch under reduced light, I would suggest that you try some of the Lance Leaved types, such as Red Frill, Lance Whorton, or White Wing. These produce a large number of leaves and are short.
Growing Indoors: STARTING CALADIUM POTS INDOORS
- I live in Tennessee and if I plant my caladiums after the weather turns warm, by the time they get full and beautiful, the early frost kills them. I dug all of them early and brought them into the house (What a job with all these pots!). Will they grow indoors? Any suggestions for next year?
Answer: I empathize with you and your cold weather. That is why I live in Florida! I would suggest that you start the caladiums in 6 inch pots next year about 3 weeks before you are ready to set them in your outdoor beds. They do not take up much space if you stack them in a pyramid and cover them with a blanket to keep them warm. Then, when you start to see the leaf sheathes just protruding from the soil surface, spread them out until you plant them outdoors. This will give you another month to enjoy these beautiful plants.
Growing Indoors: CUT CALADIUM LEAF FOILAGE FOR VASES
- Greg wants to grow caladiums for use as cut foliage and wants to know if can they be refrigerated?
Answer: The Lance Leaved Caladium cultivars generally have more leaves and last longer when cut than the Fancy Leaf varieties. However, all caladium varieties do well as cut leaves in vases. The caladium leaves will wilt intitially after cutting. Give them a little time and they will perk up and last for weeks in a vase. Remember that caladiums are tropical plants and cannot be refrigerated for storage. The cold will cause the leaves to wilt and whither.
Planting: HOW TO TELL THE TOP AND BOTTOM OF CALADIUM BULBS
- I recently bought some caladium tubers and I don’t know which is the top and which is the bottom. One side has bumpy knobs with some fuzzy roots and the other side is smooth. Help please……
Answer: It can be confusing to gardeners who buy caladium tubers for the first time and can’t determine up from down. Generally, people receive the caladium tubers prior to the development of leaves or even before the tubers begin to spike. All they see is a dried brown mass with some squiggly dried brown roots left over from the previous season. The top of the tuber has the dormant eyes, which will develop into the beautiful leaves, and the bottom has a smooth sterile surface. What is confusing is that the new roots develop around the eyes on the top of the tuber and not on the bottom as with other bulbous crops such as lilies, gladiolus, etc. This is why it is so important to cover the caladium tubers with at least 2 to 3 inches of soil when they are planted so that the young roots do not get too hot or are allowed to dry out.
Planting: STARTING CALADIUM BULBS EARLY INDOORS
- Since I live in Minnesota, how can I get caladiums to start growing earlier so that I can enjoy them longer during the season? If I wait until it warms above 55°F, I don’t have plants until July.
Answer: Realistically, the only way to get your caladium plants to grow sooner in the year is to start them indoors where temperatures are above 65°-70°F. You could start them in pots where it is warm and transplant them in bulk when outside temperatures are better for these tropical plants. Remember to water them in the pots with “warm” water, not from the typical faucet water of Minnesota. One of our greatest concerns with northern customers starting their bulbs early is the temperatures that they may encounter in transit from our farm to your location. If they get too cold in transit, the bulbs could rot and or have delayed or stunted growth. If you choose to have an early ship date, we ask you to accept and understand the responsibility that damage may occur in transit.
Planting: PRODUCING MAXIMUM CALADIUM LEAVES
- How do I get my caladiums to produce more leaves? I've heard that planting them upside down will cause more leaves to develop.
Answer: Planting caladium tubers upside down only delays leaf emergence. It does not cause more leaves to form. The best way to get more leaves is to "de-eye" the tubers before planting. Using a thin sharp knife, remove the center one-eighth inch of each large dominant eye (bud), or use a large nail to punch the center of each main eye about one-quarter inch deep. This kills the main bud and forces the lateral buds to grow and form more, but smaller leaves.
Planting: PEAT MOSS USAGE
- Is peat humus the same as peat moss and which should I use?
Answer: Humus is any composted material, such as garden waste that you would use in a compost pile in your home garden. Peat is actually a form of humus from partially decomposed plant materials. Thus peat moss is a form of humus. I have seen bags of compost that say they contain peat moss and composted organic matter. These could be used as supplements in growing caladiums but make sure the mix is not “hot” with high levels of ammonium nitrogen. High ammonium levels could burn the roots as well as encourage the development of fungal caused diseases. I prefer adding peat moss to the potting medium at 40 to 50%. Be sure to supply calcium to the mix so you get healthy plants.
Troubleshooting: BROWN SPOTS AND HOLES
- What causes the brown blotches and holes on the leaves?
Answer: The large holes in the caladium leaves are probably a combination of too much sun and a Calcium deficiency. I would cut off the affected leaves and then try to sprinkle a little gypsum or hydrated lime around the base of the plants and then water it in thoroughly. I would then try to keep the foliage moist with a daily sprinkle. Symptoms of calcium deficiency in caladiums start as tan interveinal blotches then turn a darker brown after 7-10 days. Then, the brown areas dry up and the center of the dark area disintegrates, leaving a large hole that looks like an insect ate it. Holes and leaf bruising in caladiums are also caused by damage to the leaves with hard rains and sprinklers. When water droplets lay on the leaves during the heat of the day, the sun can burn a hole right thru the leaf. It is best to plant sun tolerant caladium varieties in the full sun areas because they have a more hearty, thick leaf.
- Are there any fungi that impact caladums?
Answer: Fusarium is a major fungus disease that can infect your caladium bulbs. It can cause your caladium plants to wilt and yellow. The ideal ratio of nitrate nitrogen to ammoniac nitrogen would be 60:40. This is because Fusarium thrives on lower pH and the more ammoniac nitrogen you have, the lower the pH when it dissolves into the substrate. Chemical companies use this form of nitrogen because it is cheaper. Organic forms of nitrogen are also not the best as they break down to ammoniac nitrogen and then lower pH. Add a little lime to the soil, not only to raise the pH but to give the roots a source of calcium. Calcium deficiency results in brown blotches in the caladium leaves and eventually large holes in the leaves.
Troubleshooting: SOMETHING’S EATING MY CALADIUM LEAVES
- My caladiums are beautiful in my garden but something is eating the leaves right down to the stalk. We do have deer in the area but you said they probably wouldn’t graze on caladiums. What could be eating them?
Answer: Caladiums, especially the tubers, contain crystals of oxalic acid, which would cause a nasty taste in an animal’s mouth, similar to that found in many aroids. This bad taste is usually enough to deter animals from eating them. Wild and domestic pigs will uproot the tubers, but they usually leave them alone after a few nibbles. We have had northern customers share with us that deer are eating their plants. In talking to customers and through our personal experience, it seems to depend on your deer. Some people have lots of deer in their yards and have no problems with them eating their caladiums while others find their plantings to be deer snacks. In this instance, customers have found success with shaving Irish Spring bar soap into the plantings or placing moth balls around as deterrents. Anise (licorice plants) have also been recommended as natural deer deterrents. Products are also available at garden centers that may be helpful.
If you don’t have deer, your culprit could possibly be grasshoppers (large lubbers) or some type of worm, such as an armyworm. Generally, grasshoppers eat only parts of the leaves, leaving large holes readily apparent as you view them. The grasshoppers tend to be visible in the early morning or in the late evening when the leaves are damp and luscious. If you see grasshoppers, a few good whacks with a flyswatter or trapping them between two boards is very effective. I have found them to be great bass bait and have done very well in the local ponds catching fish. If you don’t see grasshoppers, the next choice would be army worms. Look on the underside of the young leaves to see any larvae that might be crawling around. Also, check the soil at the base of the leaves to see if any worms are curled up in the upper surface of the soil. They love to hide there during the day and forage at night. If you want to try a preventative spray purchase some form of Baccillus thuriengensis, a bacterium that disrupts the intestines of the young larvae, causing them to die. It is only effective for young larvae and does little for large worms. Your other choice is to pick them off the plant and squish them. Not a pleasant task, but effective.
Winter Storage: WHEN TO DIG UP CALADIUM BULBS?
- I love the caladiums that you send but do I have to dig them up in the fall and store them during winter in a warm place?
Answer: This seems to be a popular question. Since caladiums are tropical plants with a center of origin in Brazil, they do poorly when temperatures get below 60°F. People want to plant them like Hosta or daylilies and leave them in the ground, sometimes covered with heavy mulch. The caladium bulbs may be placed in a potato sack , open tray or cardboard box. Just make sure they are able to breathe. Caladiums are not like other spring bulbs. They can’t tolerate the cold winter temperatures. If you have access to a fungicide, dipping the tubers after digging in a fungicide solution will help to keep them healthy for the next year. It takes a little work to save the tubers, but you will get the satisfaction of seeing those colorful leaves next spring. If you live in Orlando, FL or south, you may leave them in the ground. Otherwise, dig the tubers when the leaves start to die back after the first frost.