Botanical Growing Help
Cold stratification is the process of subjecting seeds to both cold and moist conditions. A seed of many trees, shrubs, and perennials require these conditions before germination will ensue.
In the wild
In the wild, seed dormancy is usually overcome by the seed spending time in the ground through a winter period and having its hard seed coat softened up by frost and weathering action. By doing so the seed is undergoing a natural form of “cold stratification” or pretreatment. This cold moist period triggers the seed’s embryo; its growth and subsequent expansion eventually break through the softened seed coat in its search for sun and nutrients.
In its most basic form, when the stratification process is controlled, the pretreatment amounts to nothing more than subjecting the seeds to storage in a cool (ideally +1° to +3°C; not freezing) and moist environment for a period found to be sufficient for the species in question. This period of time may vary from one to three months.
To accomplish these seeds are placed in a sealed plastic bag with moistened vermiculite (or sand or even a moistened paper towel), which is refrigerated. Three times as much vermiculite as seeds are used. It is important to only slightly dampen the vermiculite, as excessive moisture can cause the seeds to mold in the bag.
Soaking the seeds in cold water for 6–12 hours immediately before placing them in cold stratification can cut down on the amount of time needed for stratification, as the seed needs to absorb some moisture to enable the chemical changes that take place.
After undergoing the recommended period of stratification, the seeds are ready to be removed and sown in the nursery bed for germination.
Alternatively, the seed may be sown in small pots filled with moist soil and then the whole thing enclosed inside a plastic bag before placing inside a common refrigerator.
Preparing a stratifying medium
Many sources recommend using peat, a combination of peat and sand, or vermiculite as the medium for cold stratifying seeds.The medium must be sterile to prevent harm to the seed by pathogens including fungi.
Preparing the seed
The seeds should be cleaned of any additional material (fruit pulp, leaf and seed-pod fragments, cone scales, etc.), but the shells of nuts should not be removed.
Warm and cold stratification
Any seeds that are indicated as needing a period of warm stratification followed by cold stratification should be subjected to the same measures, but the seeds should additionally be stratified in a warm area first, followed by the cold period in a refrigerator later. Warm stratification requires temperatures of 15-20°C (59-68°F). In many instances, warm stratification followed by cold stratification requirements can also be met by planting the seeds in summer in a mulched bed for expected germination the following spring. Some seeds may not germinate until the second spring.
Use of Organic fungicide
Use of a organic fungicide to moisten the stratifying vermiculite will help prevent fungal diseases. Chinosol (8-quinolyl potassium sulfate) is one such fungicide used to inhibit Botrytis cinerea infections.
Different seeds should be placed in different bags rather than putting them all into one bag, and large quantities are also best split into several small bags. That way any fungal outbreak will be restricted to only some seeds. If no fungicide is used, a close check should be kept on the seeds, removing any which show signs of mold or become soft and with a decaying smell.
If an outbreak of fungus occurs, remove the seeds and re-apply organic fungicide, then place them in a new bag with new slightly moistened vermiculite. Always keep the bag sealed. The stratifying seeds should be checked on a regular basis for either fungus or germination. If any seeds germinate while in the refrigerator, they should be removed and sown.
Sowing and seedlings
The medium/soil is not critical as long as the soil is light as well as lightly firmed down but not heavily compacted. Sterilized potting soil will minimize problems with Botrytis or Pythium fungal disease. These problems are much more likely to occur if air circulation is poor.
Most seeds need only be planted at a depth equal to their own thickness in order to germinate. Seeds planted outdoors are best planted a little deeper to avoid disturbance caused by heavy rainfall. The soil should be slightly damp but never soaking wet, nor allowed to dry out completely.
Most seedlings, whether grown in pots or beds, benefit from good air circulation which discourages fungus growth and promotes sturdy stems.
Growing from experience
Many seeds, such as Tabernanthe iboga, Prickly Poppy, and just about any that also require periods of cold stratification, require longer than normal periods of time to germinate. Iboga seeds can take up to 9 weeks. so one problem with these species is the seeds will rot before they can germinate. The most useful mediums for inhibiting rot are correct soil mixtures that will naturally contain less bacteria. Mediums such as peat moss, perlite, vermiculite, saw dust and sand all naturally contain lower amounts of bacteria than say composted soil mixtures. Even though compost is higher in organic matter and growth stimulants, such as nitrogen and phosphate, which are essential for seedling health, they also stimulate growth of bacteria that’s breeding ground for seed rot.
The thing I’ve done, with the highest rate of success, is to use growing mediums that are low in bacteria for germinating, then, once the seeds have germinated, either transplant the seedlings into better soil types, or, for anywhere from 2 to 10 weeks begins administering organic growth stimulates, such as compost tea, in liquid form to the seedlings, be careful when feeding seedling growth stimulants to only use moderate to low doses, because seedlings can easily be overdosed and die. Best to not use high nitrogen containing mediums, such as bird manure, and only use composted mediums, because composted materials release growth stimulants more evenly/slowly.
Alternately, one can merely take the germinated seedlings and replant them in soil types more suitable for speedy seedling growth. However, most nurseries merely use the same seed growing soil until the babies have outgrown their containers.
Another alternative is to place a 1/4 inch layer of compost, as one does mulch, over the tops of the seedlings, this will cause a slow release of growth stimulants to the seedlings. Albeit, such mulch applications should be repeated every 1 or 2 weeks as the growth stimulants will leach into to soil, and, by degrees, evaporate into the air.
One can also use commercial fungicides, but I wouldn’t recommend this as they’re toxic to children, pets and yourself. And to some seeds they can also be poisonous, rendering low to nil germination.
Consider that many seeds you buy from RSB have never been researched to know what fungicides will and will not kill them. So play it safe and don’t use any commercial fungicides.
With some seeds, such as iboga, use of small amounts of sawdust is useful, amounts no more than 5% by weight; because saw dust absorbs excessive amounts of extra growth stimulants that can be breeding ground for bacteria.
But it’s not altogether important if none is available, I consider it an extra preventive measure. And due to the fact that iboga seeds are hard to come by, expensive and require up to 9 weeks for germination I don’t want to take risk if avoidable. When sawdust is used you’ll need to feed the seedlings slightly higher doses of growth stimulants, because, as stated above, sawdust absorbs growth stimulants and renders them less available to plants. The best rot inhibiting soil mixture for seedlings is By weight, not volume, 50% peat moss, 25% perlite and 25% vermiculite, For cactus seeds; By weight, not volume, 40% peat moss, 20% perlite, 20% vermiculite and 20% course sand
How to Grow Water Lilies from Seeds
Water lilies come in both hardy and tropical varieties. Grow these beautiful flowers in your pond by purchasing tubers or started water lilies or by starting them from seeds. If you decide to start your tropical water lilies or hardy water lilies by seed, find a mature adult water lily plant to harvest seeds from, and you will need a plastic bag, paper towels, garden soil, a small hand shovel, white sand and several containers.
Collecting Seeds from Water Lilies
Water lilies disperse their seeds in pods. If you are interested in collecting seeds, you must wait until these pods mature. Then place a plastic baggie over the seed pod and loosely secure it to the stem with a twist tie. Allow water to fill the baggie and let the seed pod sink under the surface of the water.
Wait until the seed pod ripens and explodes. When this happens, remove the baggie with the seed pod and seeds from your pond.
Pour out the contents of your baggie into a tub of warm water. You will need to let the seeds ripen further before removing them from the tub. You will know when the seeds are ripe when the floral streamers rot away. The seeds will sink to the bottom of your tub.
Remove the seeds from the tub and divide them into viable and non-viable seeds. The viable seeds will be large and dark, the non-viable seeds will be smaller and light-colored.
Preparing Seeds for Planting
If you are working with tropical water lilies, place your seeds into a paper towel and allow them to dry in your refrigerator. You will keep your seeds in the fridge until you are ready to plant them.
If you are working with hardy water lilies, leave your seeds in water until you are ready to plant them.
Starting Your Water Lilies
When you are ready to plant your water lilies, prepare a large planting container for starting your seeds. To do this, add a couple inches of garden soil to the bottom of the container. Then fill the container with warm water. Wait until the sediment has settled to the bottom and then compress the soil.
Sprinkle your collected water lily seeds on the compressed soil and gently press them into the dirt. Finally, cover the seeds with a thin layer of white sand. This step will help you to see when your tropical water lilies or your hardy water lilies sprout.
Transplanting Your Water Lily Seedlings
Once your water lilies have sprouted a couple of leaves, they will be ready for transplanting into individual containers. Prepare your new containers by adding a layer of garden soil to the bottom of each pot. Now you are ready for planting water lilies in their own containers.
Plant one water lily in each container. Plant the seedling to the side of the container and cover it up to the top of its root ball with soil. Compress the soil and fill the container with warm water. Then submerge your water lilies in your pond.
Complete Cacti Cultivation Instructions
Planting a Cactus from Seed
Pick seed pods from existent cacti or buy commercial seeds. When it comes to obtaining seeds for your cactus, you have two options: buying seeds from a gardening store or supplier or picking your own from a cactus that you already have at your disposal. Here, you are essentially choosing between price and convenience — store-bought seeds are cheap and pre-packaged, while self-picked seeds are free but require a little more work.
- If you’re buying seeds, you shouldn’t have too much trouble finding them for sale. Many brick-and-mortar garden supply stores sell cactus seeds, while online shopping sites can allow you to effortlessly browse hundreds of varieties before ordering.
- If, on the other hand, you want to pick your own seeds, start by finding the seed pods or fruits on your cactus. Usually, these are brightly-colored offshoots of the main cactus body which bear a flower. When the flower falls off, the pod or fruit is ripe and is ready to be harvested (assuming it has been pollinated).
If harvesting seeds from cactus pods, gather the pods. Remove the pods or fruits from the cactus before they dry out. The pods should not be full of moisture but should still be damp to the touch inside. The seeds themselves, which are inside the pod or fruit can vary in appearance from cactus to cactus. Some seeds will be discrete black or reddish dots clearly visible from one another, while other seeds can be so small as to appear like sand or dust.
- “Ripe” pods with mature seeds should come off with a slight twist of the hand, leaving the interior fiber/cotton on the cactus. If the pod does not come off easily, it is not ready to be removed.
Next, harvest the seeds from the pods. Once you’ve removed all of the mature pods from your cactus, it’s time to remove the seeds themselves from the pods. Begin by using a sharp knife to slice the tops off of the pods. Next, slice down one side of the pod to expose the seeds. Finally, remove the seeds by carefully scraping them from the inside of the pod.
- Obtaining the seeds from tropical varieties of cactus can be different than obtaining the seeds from a desert cactus, but the general concept is the same — remove the fruit from the plant and open it up to expose the seeds. For example, the seeds of a Christmas Cactus, a type of tropical cactus, can be harvested by removing the blueberry-like fruit and squeezing or tearing it open to produce small black seeds.
Plant the seeds in high-drainage soil. Whether you bought seeds or harvested them from an existent cactus, you’ll want to plant them in clean, shallow containers filled with suitable soil. Moisten the soil thoroughly before planting but do not allow any standing water to remain. Next, spread the seeds across the top of the soil (don’t bury them). Finally, lightly cover the seeds with a very thin layer of soil or sand. Cactus seeds only have a small amount of stored energy and if planted too deeply will not reach the surface before they run out.
- Cacti require well-draining soil, especially desert varieties that are vulnerable to diseases from standing water. Try a mix of ⅓ compost, ⅓ horticultural sand, and ⅓ perlite.
- If the soil you use for planting hasn’t been pasteurized (it should say whether or not on the packaging), you may want to consider heating it in the oven at 300o F (about 150o C) for half an hour. This kills any pests or pathogens in the soil
Cover the container and expose it to the sun. Once you’ve moistened the soil and planted your cactus seeds, cover the container with a transparent lid (like plastic wrap) and place it in a location where the seeds will receive a good amount of sun — a sunny window is a good location. Sunlight should not be intense and constant, but should be strong for at least a few hours each day. The transparent lid will retain moisture in the container as the cactus begins to sprout while allowing light to reach the cactus.
- Be patient as you wait for your cactus to germinate. Depending on the species of cactus you are growing, germination can take anywhere from several weeks to several months.
- Tropical cacti are used to the shady environment under the jungle canopy and thus generally require less sun than desert cacti. You can usually get away with growing a tropical cactus in a brightly-lit spot that receives no direct sunlight. For instance, hanging pots under a shaded awning is a great location for tropical cacti.
Keep tropical cacti at a steady, warm temperature. While desert cacti in their natural environment are routinely exposed to extreme temperature swings (from extremely hot during the day to extremely cold at night), tropical cacti enjoy balmy, consistently warm weather. Thus, it’s a wise idea to grow tropical cacti in locations where they won’t experience intense, direct sunlight during the day or chilly cold at night. Try to keep tropical cacti at a temperature of roughly 70-75o F (21-24o C) — greenhouses are great for this.
- If you don’t live in the tropics, you’ll probably need to grow your tropical cacti indoors, where temperature and access to sunlight is much easier to control.
Repot your cacti when they are well-established. As noted above, cacti grow fairly slowly. Depending on the type of cactus you have, it should take about 6 months to 1 year to grow to roughly the size of a large marble. At this point, it’s a wise idea to repot the cactus in a different container. Like most potted plants, keeping a cactus in a container that’s too small for it can cause the plant to become nutrient-starved, inhibiting its growth and even killing it.
Allow cacti to recover from repotting in the shade. As the visible, above-ground portion of your cactus grows, its roots will as well. As your cactus becomes larger and larger, which can take years, it may need to be repotted multiple times. However, because the transplantation process can be stressful for plants, it’s important that you allow your cactus to “recover” after each time you repot it. Instead of keeping the repotted cactus in a location where it receives a good amount of sunlight, try keeping it in a shaded or partially-shaded area until its roots re-establish. Gradually re-introduce the cactus to the sun over a period of a month or so.
- To repot your cactus, use sturdy gloves or a spade to remove the entire plant, roots and all, from its growing medium. Place it in a new, larger container with the same type of soil, pack the soil around the cactus, and water.
When the first spines show, allow the plant to ventilate. In the weeks after you plant your new cactus seeds, your seedling should begin to germinate. Cacti typically grow fairly slowly, so this can take a month or more. Eventually, you should be able to see the first tiny emergence of your cactus’s spines. When this happens, start giving your cactus a chance to breathe by removing the transparent cover during the day. As the cactus grows, you may leave the cover off for longer periods of time until the plant is well-established and no longer needs the cover.
- It’s worth noting, however, that this will increase the rate at which water evaporates from the soil. This means that you’ll need to start watering. Try to do so cautiously — don’t let the soil dry out completely, but don’t ever leave standing water in the container from over-watering.
- Note that many tropical cacti won’t have spines, so in this case simply remove the cover once the seedling sprouts up through the soil
Water infrequently. Established cacti have less vigorous watering requirements than most other potted plants. Though they do require some water, their reputation as hardy desert survivors is well-earned. Most varieties of desert cactus require little water once they’re fully established. Though individual species of cactus may differ in the amount of water they require, a good general rule is to let the soil dry out completely before watering. Depending on the temperature, this means waiting for a month or longer between waterings.
- Remember that cacti experience slow, gradual growth. Thus, they don’t need very much water. Watering more frequently than is necessary can lead to problems for the plant, including root disorders that can cause the eventual death of the plant.
- Tropical cacti are something of an exception to this rule, as they are naturally acclimatized to more humid environments than desert cacti. While you can get away with a little more watering if you have a tropical cactus, you should still wait until the soil dries out before each new watering.
- To repot your cactus, use sturdy gloves or a spade to remove the entire plant, roots and all, from its growing medium. Place it in a new, larger container with the same type of soil, pack the soil around the cactus, and water.
Fertilize young plants during the growing months. Though cacti grow slowly, their growth can be supplemented during the growing months of spring and summer with the light application of fertilizer or plant food. Cacti generally require less fertilizer than other plants — try using a dilute solution of liquid fertilizer once a month. Mix a small quantity of liquid fertilizer with an equal volume of water. Use this mixture to water your cactus every second or third watering. The precise amount of fertilizer you should use can vary based on both the species of cactus you are growing and its size. Specific information should be on the fertilizer’s packaging.
Prevent rot by avoiding over-watering. One of the most common problems when it comes to potted plants is fungal rot (also called root rot). This affliction typically occurs when the roots of a plant are held in contact with moisture that is unable to properly drain, which becomes stagnant and encourages fungal growth. This can happen to most potted plants, but desert cacti are especially susceptible as they naturally require only a small amount of water compared to other plants. The best cure for rot is a preventative one: simply avoid over-watering in the first place. As a general rule, it’s better to under-water than to over-water when it comes to cacti. You’ll also want to use a good-quality potting soil with a high level of drainage for all cacti.
- If your plant has rot, it may appear swollen, soft, brownish, and/or decayed, with the possibility of splits in its surface. Often, but not always, this condition moves from the bottom of the plant up. The options for treating rot after it has set in are limited. You can try to remove the cactus from its pot, cut away any slimy, blackened roots and any dead tissue above ground, and re-plant it in a new container with clean soil. However, if the damage to the roots is extensive, it may die anyway. In many cases, it’s necessary to discard plants with rot to prevent the spread of the fungus to other adjacent plants
Gradually increase exposure to sunlight to treat etiolation. Etiolation is a condition in which a plant experiences pale, sickly growth because it is not exposed to enough light. Cacti with etiolated growth will often have a thin, flimsy quality and a pale, light-green color. The etiolated portion of the plant will grow towards a nearby light source if there are any. While etiolation is permanent in the sense that any sickly growth that has already occurred cannot be reversed, future etiolation can be curbed by ensuring the plant receives a sufficient amount of sunlight.
Don’t be frightened by natural “corking”. One aspect of the cactus life cycle with which most people are not familiar is the process of “corking”, in which the bottom portions of a mature cactus slowly start to develop a tough, brown, bark-like exterior. Though this condition can appear serious because it replaces the natural green exterior with one that appears dead, it’s not actually a sign that the plant is in any danger and can usually be ignored.
- However, you won’t want to throw a cactus with etiolated growth into intense, direct sunlight immediately. Instead, gradually increase the amount of sun the plant receives each day until you notice that its growth has become normal. Exposing any plant to drastically increased sunlight can be stressful for the plant while exposing an etiolated cactus to such levels of sunlight can be fatal.
Avoid phototoxicity by limiting sun exposure after using pesticides. If you’ve ever noticed that you’ve gotten an especially-bad sunburn after being in the water, you’ve experienced something similar to phototoxicity, a harmful malady that can affect your plant. After applying an oil-based pesticide to a plant, the oil from the pesticide remains on the surface of the plant, acting as a sort of “tanning lotion” by increasing the intensity of the sun’s rays. This can cause the portions of the plant on which the oil is present to become burnt, grey, and dried-out. To prevent this, place the cactus in a shaded location for a few days until the oil-based pesticide has done its work before returning it to the sun.
- Natural corking usually starts at the base of the plant and can slowly creep upwards. If the corking starts elsewhere on the plant, this can be a sign of a problem. For instance, if the top of the cactus and the side facing the sun bear this weathered appearance but the base of the cactus does not, this can be a sign that the cactus is receiving too much sun, rather than the result of natural corking