Showing posts with label Seeds. Show all posts
Showing posts with label Seeds. Show all posts
Sunday, May 12, 2013
Wednesday, January 2, 2013
Basic tips for successful germination
Erv Evans, Extension Associate
Frank A. Blazich, Professor
Department of Horticultural Science
Growing your own transplants from seeds indoors can give you a
head start on the growing season. In some cases, it may be the only
way to obtain plants of a new or special cultivar (variety) that is
not widely available through garden centers.Frank A. Blazich, Professor
Department of Horticultural Science
To obtain vigorous plants, start with high-quality seed from a reliable source. Select cultivars which provide the plant size, color (flower, foliage, or fruit), and growth habit you want. Choose cultivars adapted to your area. Many vegetable and flower cultivars are hybrids. They may cost more than open pollinated types, but they usually have more vigor, more uniformity, and better growth than non-hybrids.
Purchase only enough seed for one year's use, because germination decreases with age. The seed packet label usually indicates essential information about the cultivar, the year in which the seeds were packaged, the germination percentage, and whether the seeds have received any chemical treatment.
If seeds are obtained well ahead of the actual sowing date (or are surplus seeds), store them in a cool, dry place. Laminated foil packages help ensure dry storage. Paper packets are best kept in tightly sealed containers and maintained around 40oF in low humidity. A good storage location would be an air-tight jar or a sealed, Zip-Lock-type bag in the refrigerator. Some gardeners save seed from their own gardens, but these may not produce plants similar to the parents; this is especially true of hybrids.
Germination
Germination is the resumption of active embryo growth after a dormant period. Three conditions must be satisfied in order for a seed to germinate:
- The seed must be viable (the embryo must be alive and capable of germination).
- Internal conditions of the seed must be favorable for germination, that is, any physical, chemical, or physiological barriers to germination must have disappeared or must have been removed by the propagator.
- The seed must be subjected to appropriate environmental conditions, including water (moisture), proper temperature, oxygen, and for some species, light (see Table 1).
Plant |
Approximate
Time to Seed Before Last Frost Date (Weeks) |
Time Seeds
Take to Germinate (Days) |
Temperature
(oF) |
Light/Dark
Requirement |
Ageratum |
8 |
5 to 10 |
70 |
Light |
Alyssum |
8 |
5 to 10 |
70 |
Either |
Aster |
6 |
5 to 10 |
70 |
Either |
Balsam |
6 |
5 to 10 |
70 |
Either |
Begonia |
12 or
more |
10 to
15 |
70 |
Light |
Broccoli |
8 |
5 to 10 |
70 |
Either |
Browallia |
12 or
more |
15 to
20 |
70 |
Light |
Cabbage |
8 |
5 to 10 |
70 |
Either |
Cauliflower |
8 |
5 to 10 |
70 |
Either |
Celosia |
8 |
5 to 10 |
70 |
Either |
Centurea |
6 |
5 to 10 |
65 |
Dark |
Coleus |
8 |
5 to 10 |
65 |
Light |
Cosmos |
4 or
less |
5 to 10 |
70 |
Either |
Cucumber |
4 or
less |
5 to 10 |
85 |
Either |
Dahlia |
8 |
5 to 10 |
70 |
Either |
Dianthus |
10 |
5 to 10 |
70 |
Either |
Eggplant |
8 |
5 to 10 |
70 |
Either |
Geranium |
12 or
more |
10 to
20 |
70 |
Light |
Impatiens |
10 |
15 to
20 |
70 |
Light |
Larkspur |
12 or
more |
5 to 10 |
55 |
Dark |
Lettuce |
8 |
5 to 10 |
70 |
Light |
Marigold |
6 |
5 to 10 |
70 |
Either |
Muskmelon |
4 or
less |
5 to 10 |
85 |
Either |
Nicotiana |
8 |
10 to
15 |
70 |
Light |
Pansy
(Viola) |
12 or
more |
5 to 10 |
65 |
Dark |
Pepper |
8 |
5 to 10 |
80 |
Either |
Petunia |
10 |
5 to 10 |
70 |
Light |
Phlox |
8 |
5 to 10 |
65 |
Dark |
Portulaca |
10 |
5 to 10 |
70 |
Dark |
Snapdragon |
10 |
5 to 10 |
65 |
Light |
Squash |
4 or
less |
5 to 10 |
85 |
Either |
Stock |
10 |
10 to
15 |
70 |
Either |
Tomato |
6 |
5 to 10 |
80 |
Either |
Verbena |
10 |
15 to
20 |
65 |
Dark |
Vinca |
12 or
more |
10 to
15 |
70 |
Either |
Watermelon |
4 or
less |
5 to 10 |
85 |
Either |
Zinnia |
6 |
5 to 10 |
70 |
Either |
Temperature -- Affects the germination percentage and the rate (speed) of germination. Some seeds will germinate over a wide range of temperatures, others have a narrow range. Many species have minimum, maximum, and optimum temperatures at which they germinate. For example, seeds of tomato have a minimum germination temperature of 50oF, a maximum of 95oF, and an optimum germination temperature of 80oF. When germination temperatures are listed, they are usually optimum temperatures. Generally, 65oF to 75oF is best for most plants.
Oxygen -- Respiration in dormant seeds is low, but they do require some oxygen. Respiration rate increases during germination. The medium in which the seeds are sown should be loose and well aerated. If the oxygen supply during germination is limited or reduced, germination can be severely retarded or inhibited.
Light -- Can stimulate or inhibit seed germination of some species. Seeds that require light for germination include: ageratum, begonia, browallia, impatiens, lettuce, and petunia. Other plants germinate best in the dark. These include calendula, centaurea, annual phlox, and verbena. Some plants germinate in either light or dark conditions. Seed catalogs and seed packets often list germination and cultural information for particular plants. When sowing light-requiring seeds, sow them on the medium surface. Supplemental light can be provided by fluorescent fixtures suspended 6 to 12 inches above the medium for 16 hours a day.
Media
A wide range of media can be used to germinate seeds. With experience, you will learn to determine what works best for you. The germinating medium should be rather fine in texture and of uniform consistency, yet well aerated and loose. It should be free of insects, disease organisms, nematodes, weeds, and weed seeds. It should also be of low fertility and capable of holding moisture, but yet be well drained. Purchase commercial potting media containing fine particle pinebark, sphagnum peat moss, and perlite, or prepare a combination of equal parts (by volume) of these materials. Do not use garden soil to start seedlings; it is not sterile, it is too heavy, and it does not drain well. Commercial mixes have low fertility, so seedlings must be watered with a dilute fertilizer solution soon after germination and emergence. Use 1/4 to 1/2 of the recommended rate.
Containers for Germination and Growth
Plastic cell packs can be purchased or reused if sterilized. When using cell packs, each cell holds a single plant. This method reduces the risk of root injury when transplanting. Peat pellets, peat pots, or expanded foam cubes can also be used for producing seedlings. Resourceful gardeners often use cottage cheese containers, the bottoms of milk cartons or bleach containers. Just make certain that adequate drainage holes are made in the bottoms of the containers and the containers are sterile.
The importance of using sterile medium and containers can not be overemphasized. Before using containers, wash them to remove any debris and then immerse them in a solution of one part chlorine bleach to nine parts water for 5 minutes and allow to dry.
Sowing Seeds
Seedlings are often started indoors 4 to 12 weeks before the last spring frost. A common mistake is to sow the seeds too early and then attempt to hold the seedlings under poor environmental conditions (light and temperature). This usually results in tall, weak, spindly plants that do not perform well in the garden. The following provides general guidelines for sowing seeds for transplants. However, it is important to refer to the instructions on the seed packet for more specific information.
When sowing seeds, fill the container to within 3/4 inch of the top with moistened, growing medium. For very small seeds, use a fine, screened medium such as a layer of fine vermiculite for the top 1/4 inch. Firm the medium at the corners and edges with your fingers or a block of wood to provide a smooth and level surface.
For medium and large seeds, make furrows 1 to 2 inches apart an 1/8 to 1/4 inches deep across the surface of the planting medium. Sowing in rows improves light and air movement. If damping-off disease occurs, there is less chance of it spreading. Seedlings in rows are easier to label and handle at transplanting than those that have resulted from broadcasting seeds. Sow the seeds thinly and uniformly in the rows by gently tapping the packet of seed. Cover the seeds lightly; a suitable planting depth is usually about two to four times the minimum diameter of the seeds.
Extremely fine seed such as petunia, begonia, and snapdragon should not be covered, but simply dusted on the surface of the germinating medium and watered with a fine mist. If these seeds are broadcast, strive for a uniform stand by sowing half the seeds in one direction, then sowing the remaining seeds in the other direction.
Large seeds are frequently sown directly in a small container or cell pack; this eliminates the need for early transplanting. Usually 2 or 3 seeds are sown per cell. Later, thin them to allow only the most vigorous seedling to grow.
Watering
Moisten the planting medium thoroughly before planting. After seeding, spray with a fine mist or place the containers in a pan or tray that contains about 1 inch of warm water. Avoid splashing or excessive flooding, which might displace small seeds. When the planting mix is saturated, set the container aside to drain. The medium should be moist but not overly wet.
The seed flats must remain sufficiently moist during the germination period. Excessive moisture, however, can lead to damping-off or other disease or insect problems. Place the whole flat or pot into a clear plastic bag to maintain moisture. The plastic should be at least 1 inch above the soil. Keep the container out of direct sunlight; otherwise, the temperature may increase and injure the seeds. Many home gardeners cover the flats with panes of glass instead of using a plastic bag. Be sure to remove the plastic bag or glass cover when the first seedlings emerge.
After the seeds have germinated, move the flats to a well-lighted location; the temperature should be 65°F to 70°F during the day and 55°F to 60°F at night. This will prevent soft, leggy growth and minimize disease problems. Some crops, of course, may grow best at different temperatures.
Seedlings must receive bright light after germination. Low light intensity will result in weak, spindly, pale green seedlings. Place them in a south-facing window. If a large, bright location is not available, place the seedlings under fluorescent lights. Use two, 40-watt, cool-white fluorescent tubes or special plant growth lamps. Position the plants 6 inches from the tubes and provide 16 hours of light daily. As the seedlings grow, the lights should be raised.
Transplanting
As the seedlings grow, they will require more space. Plants not seeded in individual containers must be transplanted. A common mistake is to leave the seedlings in the flat too long. The ideal time to transplant young seedlings is when the first true leaves appear, usually 2 to 3 weeks after seeding.
Containers should be economical, durable, and make efficient use of available space. Individual pots or plastic cell packs can be used. Another possibility is compressed peat pellets which expand to form compact individual units when soaked in water. They waste no space, do not fall apart as easily as peat pots, and can be set out directly in the garden. If you wish to avoid transplanting seedlings altogether, compressed peat pellets are excellent for direct sowing.
Dig up the small plants carefully with a knife or plant label. Let the group of seedlings fall apart and pick out individual plants. Ease them apart gently; avoid root injury in the process. Handle small seedlings by their leaves, not their delicate stems (Figure 1). Punch a hole in the medium into which the seedling will be planted. Plant a seedling at the same depth it was growing in the seed flat. Firm the medium and water gently. Newly transplanted seedlings should not be placed in bright, intense light for a few days after transplanting; shading may be needed. Keep them away from sources of direct heat. Continue watering and fertilizing as in the seed flats.

Hardening is the process of conditioning a plant for growth outdoors. If plants produced inside are planted outdoors without undergoing a hardening period, their growth could be severely limited. Hardening is most critical with early spring crops, when adverse climatic conditions can be expected.
Hardening is accomplished by decreasing temperature and relative humidity gradually, and reducing water. This procedure results in accumulation of carbohydrates and thickening of cell walls. A change from a soft, succulent type of growth to a firmer, harder type is desired.
The process should be started at least 2 weeks before planting in the garden. Place plants outside in a protected area on warm days, and increase the length of exposure gradually. Do not put tender plants outdoors on windy days or when temperatures are below 45°F. Even cold-hardy plants will be injured if exposed to freezing temperatures before they are hardened.
The hardening process is intended to slow plant growth; but if carried to an extreme, significant damage can occur. For example, cauliflower will produce thumb-size heads and fail to develop further if hardened too severely; cucumbers and melons will stop growing entirely.
Further Reading:
- Bryant, G. 1995. Propagation Handbook. Stackpole Books: Mechanicsburg, Pennsylvania.
- Dirr, M. A. and C. W. Heuser, Jr. 1987. The Reference Manual of Woody Plant Propagation: From Seed to Tissue Culture. Varsity Press: Athens, Georgia.
- Hartmann, H. T., D. E. Kester, and F.T. Davies, Jr.and R. L. Geneve. 1996. Plant Propagation, Principles and Practices, 6th ed. Prentice Hall: Upper Saddle River, New Jersey.
- McMillan Browse, P. D. A.. 1978. Plant Propagation. Simon and Schuster: New York.
- Nau, J. 1993. Ball Cultural Guide: The Encyclopedia of Seed Germination, 2nd ed. Ball Publishing: Batavia, Illinois.
- Toogood, A. 1993. Plant Propagation Made Easy. Timber Press: Portland, Oregon.
Monday, February 27, 2012
How to grow Sweet Peas
(Sweet Peas Org) Sweet Peas are actually very easy to grow. You can simply plant them in the soil where you intend them to grow in March or April in the UK (be guided by local weather conditions) and leave them to it. By July you should have flowers. However, to get the best from your seeds you should consider planting them in autumn (late September to early November) or winter (January to February). This will enable you to have stronger and earlier flowering plants.
A summary of the Sweet Pea year :
September/October
Choose your varieties carefully (see Favourite Sweet Peas). Whether you wish to grow varieties for exhibition or for decoration, it pays to select named varieties from the specialist seed merchants – several of whom advertise in the Society's publications. You will tend to get better flowers and you can select your own colour combinations.
In the Midlands and the South of the UK consider planting seeds now.
November/December
You can still plant seeds now but they might need a bit of heat to germinate. You are aiming for strong compact plants so bring them up 'hard.' Keep them in a coldframe (or a cold greenhouse if you do not have access to a coldframe). Don't coddle them and keep the lights open as much as possible. Close and lag if bad weather is forecast.
January/February
You can still plants seeds now. This tends to be the favoured time for growers in the north of the UK. Nip out top two leaves when the seedlings have developed four.
March/April
Time to plant out. Be guided by local weather conditions and not the calendar. However, if the ground is cold and/or very wet it is best to wait. The plants will soon catch up.
You can plant seeds straight in the ground where you want them to grow now.
May/June
Plants will start to flower. Keep the blooms cut – if they set seed flowering will be curtailed.
July/August
Water if the weather is dry but make sure you do this early on in the day to minimise bud drop and to prevent scorching. Feed with a weak solution of your favourite plant food (formulated for flowers) if your plants are starting to look weaker. For exhibition blooms feed preferably before they start throwing blooms with only three florets to a stem.
How to prepare the site:
Much has been written on this subject but the best advice is to be governed by your own soil conditions. Sweet Peas benefit from well cultivated soil and adding a little well-rotted manure or organic compost may be beneficial. Take care not to overdo it though. Heavy soil will benefit from autumn preparation whilst the lightest soils should be prepared for planting in late winter/early spring.
How to sow:
For best results use named varieties or cultivars (see Gallery) in good potting compost and do not overcrowd – plant 1 seed to a 3 inch (8cm) pot or 6 to 8 seeds to a 6 inch (15cm) pot. Place the pots in a cold frame or greenhouse and cover them with newspaper until the seedlings have germinated. If you are planting in January to February your seedlings may need a little gentle heat to germinate. Make sure you stop the heat as soon as germination has occurred, otherwise your plants will get leggy.
Problems with germination? Some varieties have hard coats and may be more difficult to germinate. You could try soaking the seed overnight before sowing (and only sow those that have swollen) or nick the seed’s hard coat by gently rubbing against some sandpaper, on the side away from the 'eye' or scar on the seed. However, most people find that this is not necessary and there is a belief that soaking causes undue stress and weakens the plants.
How to look after your seedlings:

How to plant out:
If you want to grow your plants naturally (termed 'on the bush') set plants 8 to12 inches (20 to 30cm) apart and give them something to scramble up such as a fence with pea net, or a wigwam of canes with some string or raffia for the tendrils to catch on to. Do not forget protection against slugs, snails and birds if they are a problem to you.
Sweet Peas perform best in an open sunny site.
How to look after your plants after planting out:
Well hardened off plants should not require any further protection unless the site is particularly exposed. Let the plants get on with things themselves for about 4 to 6 weeks. If you are using the cordon method restrict the growth to the strongest shoots and tie in to the support. If you are growing your plants naturally, encourage the small plants to cling to the support by tying in at first and spreading out the shoots over the support. If your plants are particularly bushy you may have to remove some shoots to prevent overcrowding.
Make sure your plants do not suffer from lack of water but remember not to water during the hottest part of the day. Extra feeding probably will not be necessary if your soil was well prepared.
Enjoy the flowers which should start to appear from late May to early June. To prolong flowering ensure that the flowers do not set seed, take the flowers into the house and enjoy their scent.
How to grow using the cordon method:
This is the method favoured by exhibition growers and anyone wanting to grow top quality flowers. It requires more time with a commensurate improvement in blooms. You will find that you will have fewer flowers using this method than growing naturally but they will be of much better quality.

Growing on the cordon means that all the plant's energy is concentrated into producing better flowers and growth of the single branch. This means that your plants will soon reach the top of your canes. You will then need to 'layer' them. Do not confuse this with propagation – all this means is to drop your plants down to the bottom of the canes so that they can grow up again. You may need to do this more than once during the season. The easiest way to layer is to undo the ties and gently lie your plants horizontally along the rows. They will naturally turn upwards in a day or two and you can then tie them in to the nearest cane and continue as before. You may choose to tie train them up a cane further along the row straight away. Take care not to snap the plant as they can be very brittle. Choose a warm day and make any bends gradual.
Common Pests and Diseases
Mice are the greatest danger to the seed during the period of germination. Later on, watch out for birds, slugs and snails.
Aphids transmit mosaic virus. Plants start to grow poorly and have speckled leaves and flowers. Pull out infected plants to prevent the disease from spreading.
Bud drop – every Sweet Pea grower experiences this at some point in his or her growing career! In periods of cold weather the developing flowerbuds may turn yellow and fall off. Some varieties are more prone to this than others.
Leaf Scorch – leaves lose colour from the bottom upwards and dry off or 'scorch' but the plant continues to flower until the top leaves are affected.
Pollen beetles – Vast numbers of these small black insects can accumulate in the blooms, particularly on lighter coloured varieties. There is no chemical control available so the best advice is to place vases of affected flowers in a dark room with a light source at one end. The beetles will be attracted to the light and should abandon the flowers.
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