Seedlings intended for outdoors should be acclimatised to direct sunlight by placing them on a windowsill inside the house and increasing their exposure to direct sunlight by an hour or two per day.
Cannabis seedlings usually emerge from the growing medium 24 to 72 hours after the germinated seeds are planted.
Place another few layers of moist tissue on top of the seeds, again allowing excess water to drain off.
Step 3. Potting – How to germinate cannabis seeds
Check the seeds every day to ensure that the tissue does not dry out. Spray the tissues with water if necessary.
Place the cannabis seed, root first, into the hole and cover with a small amount of growing medium – just enough to block light, not enough to obstruct the seedling when it emerges.
New seedlings should be given access to bright light from the time they emerge. Care should be exercised in the first week or two, as seedlings are still quite delicate.
When the first few millimetres of root have emerged from a germinated seed, each one should then be carefully transferred to a small container of growing medium (soil, coco-fibre or rockwool).
Once your seeds have been placed and you’ve started monitoring garden temperatures, you simply need to keep them well-watered until they germinate. Too little moisture and the seeds won’t germinate; too much moisture and they could actually begin to rot instead of developing. Some seeds simply take a long time to germinate to begin with. Lavender, for instance, can take anywhere from four to six weeks to germinate. During this time, resist the urge to try to check on the seeds or disturb the oil. Instead, just continue watering as needed and monitoring your sensors.
Make sure you are planting the seeds at the correct time of year for the region you live in for the best yield. Seed packets may have ideal planting times listed on the package, or you can check a seed planting calendar online.
If your seeds have failed to germinate, even given the above tips, it is fully possible the seeds themselves were duds. If seeds weren’t stored properly — they could have been left in a hot mailbox, for instance — they may simply not be able to germinate. If seeds were stored in a very cold area, they may be taking some time to “wake” up. And there are some seeds that simply cannot germinate; many seeds that are culled from grocery store vegetables and herbs, for instance, are never going to be able to germinate.
4. Keep Them Well-Watered
This also means that you will want to keep your seeds in a place that is naturally warm and well-lit. In the early days of your seedlings, they may not need much direct light — but they will still need some sunlight. You can also invest in UV lamps, which will have a dual purpose of both providing additional light for your seedlings and also making them warmer. Most seedlings prefer temperatures that are between 60 to 70 degrees. If you purchased a seed packet, it may state the ideal temperatures for the seed on the packet. Otherwise, you can check an online soil temperature chart for the seeds you are planting.
There’s only one catch: if you start your seeds inside, you need to harden them before planting them outside. That means slowly acclimating them to an outdoor environment before being planted, starting with one or two hours outside a day. And remember, many plants are actually suitable to an indoor garden. Herbs and some vegetables can be grown quite happily inside or in pots — so you don’t necessarily need to move your plants outside.
Among the most critical stages in the growth of garden vegetables is seed germination. Germination is the process in which a seed grows into a new plant. There are a lot of variables that can come into play during seed germination, and in turn, a lot of things that can go wrong. Therefore, educating yourself on the important factors affecting this process can help ensure a successful garden.
If you’re failing to germinate seeds outside, starting them inside can help. Purchase a seed tray and plant a few seeds in each one. After your seedlings have grown, you can then move them outside to continue to develop. This protects your plants during their most vulnerable period, and lets you completely control the amount of water they get. In the early stages of growth, a single storm could wipe out your new plants!
Most seeds will not germinate without sunlight and will perform best with 12 to 16 hours each day. Indoors, place seed containers in a sunny, south-facing window and give the container a quarter turn each day to prevent the seedlings from overreaching toward the light and developing weak, elongated stems. Also, gently brush the palm of your hand against the tops of the seedlings to encourage strong stem growth.
Once you are ready to sow, you can test the viability of many, but not all, seeds by soaking them in water for a few hours. The seeds that are still living will sink to the bottom, while the dead ones will float on the surface. This test generally works better for larger seeds, but there are no absolutes.
Before seedlings can be planted outdoors, they need to be hardened off, or acclimated to direct sunlight and fluctuating temperatures. It is best to do this over a three-day period by placing them in direct sunlight during the morning only of the first day, then increasing their time outside by a few hours each day until they are vigorous enough to be transplanted.
8. Turn seedlings daily to keep stems strong
Most seeds require temperatures of 65° to 75°F to germinate. Placing seed containers near an existing heater or using a space heater with the proper precautions can raise the ambient temperature as needed. In addition, a heating pad designed for plant use placed directly under the seed containers will warm the planting mix and encourage germination. When using any additional heat source, be sure to check for moisture often, since the seed containers may dry out more quickly.
To promote good air circulation, place a small fan near your seedlings. Keep the fan on low and direct it to blow across the containers at the soil level where air may become trapped and stagnant.
Few gardening pursuits are as rewarding as growing your own plants from seed. As the nursery manager at the Thomas Jefferson Center for Historic Plants at Monticello, I have started thousands of ornamental and vegetable plants from seed. Growing plants from seed is not always an easy task, and over the years I have developed and adopted the following techniques to ensure that seeds get a healthy start.
Use a kitchen sieve to spread soilless seed-starting mix evenly over the top of the seeds to the depth of two times the seed diameter. Very small seeds and those that require light to germinate should lie directly on the surface. Whether covered with planting medium or not, each seed must be in firm contact with the moist surface to begin germinating. Use a pestle or even the bottom of a glass to gently tamp down the surface.