Growing from seed is an addiction. Only those who are into it know the joy of successful seed germination. Here are some tips for successful seed germination. I hope other members will also contribute. Note that these are general tips, some seeds need special treatment.
1- Large seeds germinate easily and quickly as compared to small seeds. Large seeds can be soaked in water to let the moisture penetrate into the seed for germination. 2- Examples of large seeds are morning glory, sweet peas, bauhinia etc. Examples of small seeds include poppy, petunia, buddleja etc. 3- After seed is germinated, seedling will lean towards sun so keep changing the direction of container so that it remains even.
Sowing depth Larger the seed, deeper it will be sown. Smaller the seed, closer it will be to the soil. Very small seeds which can not be handled through fingers are mostly surface sown. Surface sown means just place the seeds on the soil surface and do not cover. Very light sprinkling of coco-peat or peat moss is beneficial in most cases.
Sowing time For spring blooming annuals, seed is sown in september-November For summer blooming annuals, seed is sown in February-April For perennials, seed can be sown either in September-october or in Spring (March). The optimum temperature for germination of most seeds is around 20C. Extreme heat and extreme cold both are not good for sowing seeds.
Sowing Medium Whether it is soil based medium or soil-less medium, it must be well drained. If water stands, seeds will rot. This is the reason most seed germination mixes include sand as sand improves drainage. For precious seeds, vermiculite can be used. Following mixes are successful in my experience: - 30% sand, 30% garden soil, 30% peat moss - 50% peat moss, 30% leaf mold, 20% sand
Fertilizer Somewhere i read 50% sand and 50% leaf mold but not tried yet. IF using vermiculite you can use top few inches of vermiculite while bottom can be filled with good soil mix having some light fertilizer. It is not only cost effective but also logical. Vermiculite will help in germination of seeds and when roots will develop and reach bottom they will get fertilizer.
Note that seeds do not need any fertilizer for germination, strong fertilizer will burn the seedling or seeds might not germinate. Best bet is add very little leaf mold. Another option is whenever you water your seedlings, add 1/6 strength liquid fertilizer in every watering.
Watering Before sowing the seed, water the container or soil bed thoroughly. After hour an hour, sow the seeds. After that keep the soil moist but not damp. Always use spray gun to water, the one which hair dressers use. To keep it moist and not damp, there are few options. First, use moisture meter to check the moisture, most PH meters come with moisture meter. Second, check soil color, it will tell you whether you need to water or not. third, you can check the container weight but it is more successful in clay pots as plastic pots are already light.
Try bottom watering the seeds and seedlings. There are few ways to achieve it. First, sow in peat pots and place them in 1 inch of water, the water will automatically flow up. Second option is, sow in plastic seeds trays with bottom holes. Place the seed tray in water so that the water is half an inch over the tray from bottom. Soil medium must be light to achieve that. Check bottom watering on internet as well. There are self watering trays as well and they are best for this purpose
Prevent Damping off In hot and humid weather mostly in monsoon and some times in march april, seedlings suffer from damping off. In this disease, seedlings fall flat. Try sprinkling cinnamon powder on the surface before sowing seeds and improve air circulation. There are some commercial anti-fungicide as well.
Which container to use Remember clay pots need frequent watering as they dry out quickly. plastic pots retain moisture so less watering is required. I prefer plastic pots as i lost lots of seeds due to dry out problems. In spring sowing plastic containers help less watering. In fall sowing, clay ones are also OK as weather is not harsh. I never had the problem of air circulation in case of plastic pots.
Top 2 techniques for germinating difficult seeds There are 2 techniques which i use: 1- Soon after sowing the seeds, pack the container in a polyethene bag which must be transparent so that light goes in. When you see the seed germinated, gradually acclimatize the seedling with outside temperature. Open it daily for few hours then increase it and then after few days remove it. This one i use mostly for very small seeds.
2- This method is applicable only for those seeds which are large and can be handled individually. Does not apply to very small seeds. place the seeds between moist sheets of cotton (which is used in wounds) and place them somewhere bright. just when you notice the cotton is starting to dry, water it through sprayer. This is a variation of famous Zip-Lock baggie technique for germinating seeds.
In my opinion, October is the best time to sow all perennial seeds, as the plants get established before the intense summer heat. If you sow in spring then seedling will have to go through strong summer heat. However some seeds including bignonia family seeds, passifloras, hardenbergia etc. needs temperatures into 30's to germinate.
Some extarct from an article, found useful and would like to share as most of us are thinking about the best possible ways for seed sowing. There need some slight changes for better understanding according to our enviroment, hope someone can add in..
Moisture: This is probably the trickiest part, kills most seedlings. Baby seedlings have very little root system, so cannot be allowed to dry out or they die. However they are also very sensitive to being too wet. There is a fungal condition called damping off that young seedlings are prone to in conditions of low air circulation and too much moisture/ humidity. The stem starts kind of rotting just above soil level, gets a little bit pinched in and the seedling keels over, ends up lying flat on the soil. Once that happens, it is kaputt, all you can do is get rid of it. So you need to provide consistent barely damp, preferably with good air circulation. Easiest way to do that is by "bottom watering": having all your cells/ pots/ containers in trays. Then you just pour a little water into the bottom of the tray, just until it just touches the bottom of the pots, so the soil in the pot can wick it up. Probably add a little bit of water each day, but NOT if there is any water left from the previous day.
Containers: NOT peat pots. They are a menace. Hold too much moisture and stay too wet and then suddenly dry out and suck all the water away from the plant. And if you are bottom watering, they will get all moldy on the bottom. Use plastic. Can be the little cells and pots made for the purpose or it can be plastic yoghurt cups, drink cups, or whatever is handy as long as you put plenty of drainage holes in them. If you are using heat mats, it is typical to start plants in the little grow cells, so that you can crowd a lot of seeds onto one mat. If you do that, once they are well sprouted and have their first pair of true leaves they will need to be transplanted out into little pots.
AVOID the little seed starting kits sold with domes and peat pots, they are seedling killers! I don't use a dome at all, to easy to damp off your seedlings. If you do use a dome, remove it as soon as the seedlings are sprouted.
The main other thing you need to be aware of for seed starting is TIMING. If you start seeds too early, they will out grow your space before it is warm enough outside to put them out and you will end up with long spindly plants. If you start them too late, you will end up putting them out in the heat of summer. You need to be aware of the difference between cold weather crops, which are frost tolerant, like cool weather and tend to fizzle as soon as it gets hot and warm weather crops which die in frost and like hot sunny weather. Cool weather crops include peas, brassicas [broccoli, cabbage, cauliflower, etc], root crops like potatoes and carrots, and green leafies [lettuce, spinach, chard, kale, etc]. Warm season crops is pretty much everything else. Corn and beans are earliest of warm season, then tomatoes and peppers, and the cucurbits[squash, melons, cucumbers, etc], are the latest, need the soil really nice and toasty warm. So you want to have your seedlings ready to go out at the right time for the season they like.