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Growing house plants from seed?

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As you’ve probably gathered from my last two seed related posts, you don’t need a greenhouse and misting system to successfully propagate house plants from seed. It is really fairly simple and inexpensive.

A number of popular foliage and flowering house plants are commonly propagated from seed, including the umbrella tree Brassaia, False aralia Dizygotheca, tree philodendron P. Selloum, palms, cacti, succulents, geraniums, begonias, and impatiens.

How to Plant Seeds

Unlike seeds of many temperate woody plants, which require a storage period of moist chilling(stratification) prior to planting, the seeds of tropical plants should be sown as soon as they are mature. House plant seeds may be sown in any container with drainage holes. Use a sterilized medium which is low in soluble salts such as milled sphagnum moss, vermiculite, or a mixture of equal parts sand and peat moss. Bottom heat (between 70 and 75 degrees F) aids the germination of seeds and growth of small seedlings. Soil heating cables and mats are available in several sizes to fit individual needs. Inexpensive models for seed flats are usually preset at 72 degrees F. Larger ones, for greenhouses benches and outdoor hotbeds, may be thermostatically controlled.

Sow seeds sparingly and as evenly as you can. Seedlings that are bunched together will have poor air circulation and are likely to fall victim to damping-off, a fungal disease which attacks the seedling stems at the soil surface. If the seeds are so small that they are dust-like or powdery, sow them on top of a moist medium – do not cover them. If they are larger, the rule of thumb is to cover them to twice their diameter. When working with seeds the size of coleus, impatiens, and gloxinia, simply press them into the surface of the planting medium with the palm of your hand.

Label each container with the variety planted and the date. This is a handy reference when you want to determine how long it takes certain plants to grow from seed to maturity. If you want to experiment with different growing methods, be sure to add other information to the label, such as growing medium used, temperature, mist or bottom watering, or depth of planting.

With nearly all seeds, it is imperative to keep the medium moist, but not soaked. Containers with drainage holes can be soaked in a sink or shallow tray of water. Those without drainage can be moistened by misting the surface with tepid water or carefully adding the needed water with a tablespoon. If you are working with very small seeds, it is a good idea to put a clear glass or plastic cover on the container to maintain the moisture, since they germinate better in high humidity. If too much water is added, leave the cover off until the surface appears to have dried out somewhat.

Care of Seedlings

When seedlings show above the soil, they should be moved to brighter light. The first one or two leaves that sprout from most seeds are cotyledons, which nourish the stem tip and the foliage leaves which follow. Until the foliage leaves appear, do not allow direct sunlight to reach the seedlings for more than a few minutes daily. You can determine the amount of light seedlings need by learning the light requirements of the mature plant. For example, geranium seedlings need more sunlight than rex begonia seedlings. An ideal place for seedlings is 3 or 4 inches below a pair of 40-watt fluorescent tubes.

When seedlings are started in a high-humidity container, it is necessary for them to go through a hardening-off period to become accustomed to the drier conditions of the open air. Leave the container’s cover off for an hour or two each day after the sprouts appear. As the seedlings progress, leave it off all day or night, finally removing it entirely. Be careful not to let the growing medium dry out during this process.

Transplant seedlings before they begin to crowd each other, usually as soon as the first true leaves develop. They can go into small, individual pots or several seedlings can be transplanted into one flat or a large pot to save space. As they grow, the largest ones are transplanted into separate containers. Use your fingers and a flat instrument like a nail file or butter knife to separate and lift tiny seedlings. Handle them by their root balls or leaves; it is very easy and usually fatal to crush the stems. Reset them at approximately the same depth as they have been growing and firm the soil gently around the roots. Water thoroughly from below.

Until the plants are established, keep them in a warm, bright place, but out of direct sunlight. Create a high-humidity environment, if possible – it is especially beneficial to plants at this stage. As soon as seedlings begin active growth, fertilize every two weeks with diluted liquid plant food. If the container does not list a strength recommendation for seedlings, mix the fertilizer at one-third to one-half the rate suggested for house plants.






Houseplants- swollen leaves and edema

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Have you noticed that occasionally some of your plants will get swollen blister like areas on their leaves or fleshy stems? I went through a period of that with one of my Christmas Cactus’ for two years straight. I’m happy to report that it’s not happening this year though.


Sometimes the spots are tan at first or they become dark brown and become wart like. Corky bumps occur most often on the underside of the leaves of succulent plants such as jade plant and peperomia. Of course they could occur these bumps could occur on other plant parts, and on other types of plants as well such as Swedish ivy, schefflera, croton, geranium or begonia.

It this were to continue the leaves will turn yellow and droop, and then fall from the plants. Plants can become spindly and cease to grow as result of this condition which is called edema. It is often found on indoor plants in winter. It’s caused by environmental factors – a build up of water pressure in the leaf tissues will result in dostortion and busting of cells.

Overwatering, high humidity, and low light intensities favor the development of edema. Faulty watering practices, such as allowing plants to dry out completely and then drowning them, encourages it. Avoid overwatering susceptible plants, especially during the winter months when they should be kept slightly on the dry side.

Differences in potting medium, environment, and the individual plant type influence water needs. If the soil feels or looks damp in a pot, don’t water. Allow the soil to dry out somewhat, then water deeply until water drains out of the hole in the pot’s base. This insures that all of the plant’s roots receive water and it leaches out excess minerals accumulated in the soil. Make sure to empty water out of the saucer beneath the plant so the roots do not sit in water.

If edema occurs, keep the relative humidity below 70% in the vicinity of the plants. Improving air flow over the leaves by spacing plants further apart and increasing ventilation will help reduce humidity. Inexpensive humidity meters which can help you monitor the plants’ environment can be bought at garden centers or through catalogs. Moving the plants to a sunny location or adding supplemental artificial lighting is also beneficial.

Leaves showing symptoms of edema will not recover, but you can halt the decline of a plant by improving light and watering less often. Repotting to improve soil drainage may also help. Affected plants often recover from oedema with the return of more favorable growing conditions in spring and early summer, especially if they are placed outside as soon as weather permits.

Your home and toxic houseplants

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Have you ever thought about, or wondered as to how many house plants that are currently in your home would be unsafe if eaten by a child, pet or even an adult? Not that adults are going around eating leaves off houseplants- but either way, some of the plants we have in our home are toxic and often the plant owner doesn’t realize just how dangerous they could be.

I’ve compiled a list of plants that have toxic properties. I’m not advocating removing them from your home- just that you be aware of which plants are toxic and what kinds of symptoms they can cause. Any plants in your home that are known to be toxic should be placed well out of reach of small children or house pets.

Members of the Araceae family

These plants contain needle-like crystals of calcium oxalate that penetrate and irritate tissues of the mouth and throat. Chemicals in their sap, such as asparagine, a protein, also can cause inflammation of mucous membranes. Plants in this family include dieffenbachia, philodendron, caladium, and elephant’s ear. Symptoms of poisoning from dieffenbachia are intense burning and irritation of the mouth, tongue, and lips. Although rare, if the reaction is severe enough, the swelling can seal off the breathing passages. Philodendron, caladium, and elephant’s ear produce the same types of symptoms when ingested. If a piece of the corm, the underground stem, is eaten, symptoms are a fiery burning of the mouth and throat. Jack-in-the-pulpit is a native member to watch in this family.

Members of the Euphorbiaceae (spurge) family

Most members of the spurge family have a milky sap this is acrid and toxic. This sap can cause dermatitis in some people and poisoning if eaten by someone who is allergic to the chemicals in the sap. Members of this family include the crown-of-thorns, the pencil tree also know as the milk bush, poinsettia, and snow-on-the-mountain. Snow-on-the-mountain can cause blisters and skin burns.

It is appropriate to note here the debate about the poinsettia. The original warnings on this plant were from a report in 1919 on a child who died in Hawaii where poinsettia is used as an outdoor ornamental. However, laboratory tests have NOT confirmed the toxicity of the plant when ingested. Poison control centers receive many reports each year of ingestion of poinsettia, but only occasional abdominal pain and nausea have been documented.

Members of the Solanaceae family

These plants contain solanine, a poisonous glycoalkaloid, that is extremely toxic even in small amounts. Jerusalem cherry is an ornamental in this family. Eating its berries cause symptoms ranging from headaches and stomach pains to shock and paralysis of the circulatory and respiratory systems. However, not all members of the Solanaceae family are toxic; for example, tomatoes and peppers.

Now that you are aware of possible dangers with certain houseplants, you can take steps to ensure the safety of others around these lovely plants. Try using hanging baskets, high shelves, or window boxes to keep plants away from children. You don’t need to stop displaying the plants mentioned above, just do so carefully.

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