How to Start Annual Seeds Indoors

You can save money on annuals by starting them from seeds rather than buying them in containers at the nursery. You can also easily get the exact plant you want, ordering packets of seeds from seed catalogs, which have a much wider selection of varieties than the typical nursery. It is a simple matter of germinating the seeds and tending to the seedlings.

Some good annuals for starting indoors are Statice (limonium sinuatum), Globe amaranth (gomphrena), Sweet asylum, Bell of Ireland (molucella laevis), zinnias, torch flower, bachelor’s button (centaurea cyanus) and strawflower (helichrysum).

You will need the following:

- Seed starting containers
- Soil-less seed starting mix
- Light source, such as grow lights, florescent lights or a greenhouse.
- Mist sprayer
- Liquid fertilizer
- Plastic wrap
- Shallow plastic trays
- Seeds

For the containers, you can use small paper cups, aluminum pie pans or the small plastic containers sold in garden supply shops. To keep the soil moist, these containers should be placed in a larger one, like a plastic tray, filled with water. Don’t make the mistake of putting your seeds or seedlings in egg cartons, they will not hold enough soil to keep moist.


Start by filling your containers with soil-less seed starting mix, which typically is a mix of fine vermiculite, peat moss and pearlite. The reason you shouldn’t use soil is that it may contain fungus which can cause seedlings to rot.

Using a pencil or your fingertip, make a small depression in each container for the seeds. The rule of thumb is to make the hole 3 times as deep as the width of the seed.

Into each hole, drop one or two seeds and cover them up with pinches of the seed-start mix.

Thoroughly dampen the seed start mix “soil”. Use a mist sprayer so you do not flood the planted seeds from their depressions. Alternately, place the containers in trays filled with an inch or so of water; after an hour, the containers will absorb enough water to saturate the soil.

Cover the planted containers with plastic wrap to keep them from drying out. You could alternately enclose the whole tray in a large plastic bag.

Place the containers in a warm place. (On top of refrigerator, near the furnace, or near a baseboard heater) Check for germination after 3 days. Germination is what happens when the hard seed coating becomes softened by moisture and a sprout emerges. Once the sprout is out, seedlings need sunlight.


Once you see the first sprouts sticking out of the soil, remove the plastic wrap and place the seedlings where they will receive good light. We recommend using some type of supplemental lighting, such as a small tabletop florescent fixture. The seedlings should be approximately 2 inches from the lights. Lighting should be left on 12 to 16 hours each day.

The next step is to thin out your seedlings. If the plants get too crowded together, they won’t be able to grow to their best ability, so make sure that they are at least 2 inches apart on all sides. Once seedlings have reached one inch or so in height, use tweezers or your fingers to pull out the weakest growths. It might seem cruel, but it is for the good of the other plants. It is best to get this over with before roots have had a chance to entangle.

If you cannot bear to get rid of any the weaker plants when thinning out, then try thinning by dumping the soil from the container. Find the seedlings in the soil and gently disentangle the roots from each other if needed, and transplant all the seedlings to individual containers. Just be sure to handle the seedlings by their leaves, and do not ever hold them by their stems.

Two weeks after the seedlings have first sprouted, it is time to fertilize them. Use a liquid fertilizer which can be diluted with water, mixed at half normal strength. Fertilize the seedlings once per week.

Your annual seedlings should be ready for transplanting to the outdoors in four to six weeks. It is recommended to use a process called hardening off, where you gradually accustom the plants to the outdoor environment. This involves setting the seedlings outside a few hours the first day, and gradually, over a period of one to two weeks, increasing the amount of time they are outside until they stay out the entire day. If the temperature outdoors goes below 50F (10C), then move the seedlings indoors. After the hardening off period is over, the plants are ready to be transplanted into their permanent outdoor location.

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