How to Start Seedlings Inside for Spring Planting


Learning how to start seedlings inside for spring planting is not as hard as you might expect. As long as you have the proper supplies, sunlight, and patience, you can get a jump start on mother nature and ensure your plants are healthy when the time comes to move them outside.

Materials and Supplies

Before planting, gather the needed supplies and make sure you have space to keep your seedlings until they are ready to move to the garden. It is better to start less varieties than to crowd them.

The proper soil is essential to growing healthy plants. Purchase a sterile mix designed specifically for indoor planting. This type of soil will have the necessary fertilizer already mixed in and should not require additional amendments.

Containers are another important aspect to successful indoor plantings. There are several types of containers available and the most commonly used are peat pots. These are biodegradable so they can be planted directly into the ground once the seedlings are transplanted. This is especially helpful as fragile seedlings may be difficult to remove from pots without harming the roots.

Seed varieties suitable for transplanting are a key to successful indoor gardening preparation. Not all types of plants transplant well so consult your seed catalogs, garden center, or local extension office to be sure. If you are a novice gardener, you may want to stick to just a few varieties your first season until you know how much time and effort it will take compared to the amount of time you have.

Incubators or warming mats are the easiest way to keep tender seedlings growing. Unless you have a very sunny spot where the sprouts can get daily sunlight, it is advisable to invest in something to keep your plants warm. Without sufficient warmth, the seeds will not sprout.

How to Start Seedlings Inside for Spring Planting

Most seeds used for indoor planting can be started indoors six to eight weeks before they need to move outside. Determine the last frost date for your area by consulting the USDA Hardiness Zone map and count backwards from that date to know when to start your seedlings.

Fill your containers with sterile seedling soil mix and water thoroughly. The soil should be moist but not soaked as this may lead to seed rot. Plant your seeds in each pot according to the planting depth noted on the seed packet. Take care not to plant too deep as this may prevent your seed from sprouting. For seeds meant to be planted at a very shallow depth, you may want to simply sprinkle the seeds on the soil's surface then add a thin layer of soil mix over them.

Place the containers on a warming mat or inside the seedling incubator. If you are using an incubator, keep the light turned on for several hours each day to ensure the plants are getting properly warm so they will sprout. Take care, however, not to keep it too warm as this may cause the seedlings to wither and die. The seed packets typically identify how many days you can expect before your seedlings sprout so keep an eye on your containers to ensure the majority of your seeds sprout in the allotted time.

Check the moisture levels every few days to ensure the pots are not drying out. Water as needed but remember not to keep too wet. After the last frost date in your area has passed you can plant your seedlings directly in the garden. You may want to set them outside during the day for several days before planting so the seedlings can get used to the outside temperature and harden off.

Keep a Journal

Now that you have learned how to start seedlings inside for spring planting, keep a gardening journal to document the season. Record what varieties you planted and how long it took for them to sprout. Other journaling notes should include the number of plants that did not thrive, the amount of sunlight and water you provided and whether any varieties of seedlings had trouble once they were transplanted into the garden. By understanding what worked well and what did not, you can tweak your garden plans for the next spring and optimize your yields.

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How to Start Seedlings Inside for Spring Planting