How to Grow Plants from Seed
Set the planting time., Select a starting pot., Add seed starting mix., Plant your seeds., Cover seeds based on their size., Seal moisture in with plastic., Keep the seeds in warm, indirect sunlight., Check moisture levels every day or two., Remove...
Step-by-Step Guide
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Step 1: Set the planting time.
In most cases, you'll want to start your seed indoors.
However, this depends on what you are planting.
For example, lettuce and green beans do better when you sow them outside directly in the ground.
This means you can plant before the spring frosts have passed.
Cold-hardy plants can be planted indoors in late winter or early spring.
Plants that thrive in heat need a later seeding date (mid- or late spring), so the weather is warm when the plants are ready to go outside.
Plants usually take three to six weeks to grow from a seed to a healthy plant ready to be moved outdoors, but some take up to fifteen. -
Step 2: Select a starting pot.
Seeds planted outdoors are vulnerable to disease, insects, and bad weather.
The survival rate will be higher if you care for the young plants indoors.
A seed starting tray from a gardening store is a convenient option, but you can use any small container with drainage holes.
Before reusing an old container, scrub thoroughly with soapy water.
Dip it in a solution of one part household bleach and nine parts hot water, then air dry.
This will kill microorganisms that could harm the seed.Some plants such as lettuce, cucumbers, melons, and sunflowers suffer when transplanted if their roots are disturbed.
You can start these seeds outside instead after the last spring frost, or plant each seed in a separate cell of a "plug tray" and transplant the whole chunk of soil., Making your own is simple, and much cheaper than buying it from a store.
Just mix together equal amounts of perlite, vermiculite, and coir (or peat moss).
This light mix drains quickly to prevent rot, and makes it easy for the sprout to emerge from the surface.Moisten the seed starting mix thoroughly, then fill containers to within ¼" (6mm) of the top.
Use any clean object to gently press the mix into a firm, level surface.
Let excess water drain before you continue.
If you're using a store-bought mix, check whether it contains compost.
If it does, you won't need to fertilize your seedlings. (Don't try to add compost to a homemade mix for your first project — it's more trouble than it's worth.) If you use peat moss instead of coir, add hot water to make it easier to mix in.Since peat moss is acidic, it helps to add garden lime (calcium carbonate) to balance it out.
Try ¼ tsp of lime per gallon of potting mix., If the seed starting mix has dried out, moisten it again before planting.
Check your seed packet for exact spacing and planting depth instructions, or follow these guidelines:
Shared tray, one variety:
Scatter the seeds loosely and evenly across the tray.
Shared tray, multiple varieties:
Scratch shallow rows 1–2 inches (2.5–5cm) apart with a clean ruler.
Drop seeds of each variety into a separate row.
Label each row.
Separate pots or plug trays:
Plant one large seed (e.g. cucumber or melon seed) or two small seeds (e.g. most flower seeds) in each container. , As a rule of thumb, bury seeds to a depth twice the diameter of the seed.
Most tiny seeds need light to germinate, including petunia, lettuce, and snapdragon seeds.
Just leave these on the surface of the mix.
Dry vermiculite or milled sphagnum moss (not peat moss) are ideal for covering seeds, but you can use dry seed-starting mix instead.Sprinkle the material on lightly.
If you press it on hard, the sprout may have trouble breaking through the compact layer. , Seeds are very vulnerable to over- and under-watering.
A layer of plastic wrap or a plastic bag seals will often keep the mix moist until the seeds have germinated.
Most seed trays from garden supply centers come with a plastic cover to keep in moisture.
If your seed trays did not come with a cover, then you can make a miniature greenhouse instead, or grow seedlings in an old, covered aquarium. , If the seed packet doesn't specify a temperature, keep it at daytime temperatures between 65 and 75ºF (18–24ºC), and night temperatures no lower than 55ºF (13ºC).Put a heating pad under the tray if the room is cooler than this.
Most seeds do best in plenty of light, but avoid direct sunlight if the containers are covered in plastic.
Some seeds germinate best in complete darkness, including tomatoes, larkspur, calendula, and coriander.
Block the light with black plastic or cardboard.If you want to maximize success, you can look up your variety's specific temperature needs.
In most cases, though, you'll only lose a few seeds to the "wrong" temperature, or the seeds will take longer to emerge. , If the mix looks dry, place the container in a container of water.
The mix will absorb water from the base of the container.This is less risky than watering from above, which can wash away the seeds or overwater them.
As mentioned before, the plastic is often enough to retain moisture for the whole germination period.
This is just a backup. , Most seeds germinate (sprout) within a couple weeks.
Once sprouts have emerged from the soil, take off the plastic cover (if you were using one).
If you planted in rows in a shared tray, cut strips of plastic or cloth to cover the rows that have not yet sprouted., Move the container to a bright, south-facing window (north-facing in the Southern Hemisphere).
If the temperature or lighting conditions on the windowsill are very different from the last location, move the seeds in several stages, gradually increasing brightness levels.
Sudden changes may kill the plants.
If it is quite cold outside, you may need to place a heat pad between the planters and the window.
Otherwise, the cold will be absorbed through the window and slow the growth of the tiny seedlings.
At far northern or southern latitudes that don't receive much sunlight, place a grow light 6 inches (15 cm) above the seedlings and turn it on for 14–16 hours a day.
Move the lamp farther away as the seedlings grow to avoid burning them., Plants grow toward the light.
If light only comes from one window, the seedlings will lean into it and grow long, weak stems.
Give the containers a quarter turn each day to promote even growth. , Unless your seed packet says otherwise, continue to keep the plants at daytime temperatures between 65 and 75ºF (18–24ºC), and night temperatures no lower than 55ºF (13ºC).
Excessive cold or heat during this stage can cause unhealthy growth patterns, such as weak, "leggy" stems. , The mix must stay moist but not soggy, or the delicate roots will rot or drown (unable to absorb oxygen).
A water bath that lets the container absorb water from the base is ideal, since watering the sprout may break it or encourage disease.
Seeds will quickly die if allowed to dry mid-germination.
Check at least once a day. , The first set of leaves that appear are known as the seed leaves or cotyledons.
The second set of leaves are the first ‘true leaves,’ and a sign that your plant is getting mature and ready for serious growth.
Dilute a balanced fertilizer to ¼ the strength recommended on the label.
Pour it into a tub and place the container in the diluted fertilizer to absorb it from below.
Repeat once a week or as directed by the fertilizer label.
If the seeds were planted in a mix that contained compost, do not fertilize them.
Too many nutrients can cause "burns" or other problems.
You can fertilize at ½ strength once the seedlings are in larger pots, and full strength once they are adults. , If the seedlings are sharing a container, they may need a larger home to prevent them from crowding each other.
However, this isn't necessary for all seeds.
It depends on the variety.
If you do need to thin out the seedlings, delay this delicate process, until the seedling looks sturdy enough to handle it.
Typically, gardeners will only transplant the largest, healthiest seedlings.
You can compost or give away the rest.
Here's how to approach the transfer:
Wash the new container in soapy water, then rinse.
Fill the new container with moist, room temperature potting soil.
Push a hole into it large enough for your seedling's roots.
Gently tease away the starting mix around the seedlings root using a popsicle stick or similar thin tool.
Lift the plant by the topmost leaves.
Do not handle the stem.
Lower the plant into the hole.
Use a pencil to spread out the roots a little, but don't worry if it's not perfect.
Sprinkle moist potting soil over the roots until the seedling is planted to the same depth as before.
Press the soil down lightly.
Avoid changes in temperature and light levels for at least a few days, while the plant is recovering. , ‘Hardening off’ is a process in which you slowly expose your plants to the fluctuating temperature and weather conditions outdoors, so that they don’t suffer from transplant shock.
Start this process two weeks before the outdoor planting date appropriate for your plant:
Lower the temperature indoors slightly.
Water less frequently, but do not let the plants dry out.
Move them outdoors for an hour or two a day, in a shady area protected from wind.
Avoid temperatures below 45ºF (7ºC).Increase the amount of time spent outdoors by an hour or so each day.
Gradually expose the plants to sunlight. (The correct amount of sun depends on the plant and where you plan to move them.) , Once the weather is warm and your plants can handle being outdoors all day, transplant them to a permanent outdoor pot or garden bed.
Follow the specific directions for your plant, since every species has different temperature and sunlight needs.
This is the basic outline only:
When possible, transplant on an overcast morning with minimal wind.
Wet the soil both in your plant's pot and in the new hole.
Carefully transfer the root ball to the new hole.
Spread out the roots as much as you can without breaking them.
Add soil to the same planting depth as before. "Water in" heavily to bring the soil in contact with the roots. , Transplanting is rough on plants, and it can take several weeks before new roots become established.
After the initial watering, keep the plant moist but not soaked.
Protect the plant from strong wind and rain until it's back to its healthy self. , Newly sprouted seedlings die to fungus so often it has its own name: "damping off." Try again with new seeds, and take extra precautions to prevent spores from landing and taking hold:
Use sterile potting mix and clean all containers and tools with a 1:9 ratio of household bleach and water.Sprinkle dry vermiculite or perlite over the surface of the container after planting.
Avoid cool, damp conditions.
If the soil drips water when you squeeze it, it is too wet.
For best results, treat the mix with fungicide, following label instructions. , Many tree seeds, including seeds taken from oranges or apples, need special treatment to trigger germination.
Following the exact instructions for your species will provide best results.
Most seeds of this type need one or both of the following treatments:
Scarification:
Seeds with a hard coat may need it removed or thinned.
Try rubbing with a nail file or nicking it with a knife.
You can even boil some tough seeds to soften the coat.Stratification:
Many tree seeds in nature lie on the ground all winter and germinate in spring.
A few weeks in a cold, damp environment mimics these conditions so the seed "knows" that it should sprout.
Try keeping the seeds between two damp paper towels in the fridge, inside an unsealed zip-locked bag. -
Step 3: Add seed starting mix.
-
Step 4: Plant your seeds.
-
Step 5: Cover seeds based on their size.
-
Step 6: Seal moisture in with plastic.
-
Step 7: Keep the seeds in warm
-
Step 8: indirect sunlight.
-
Step 9: Check moisture levels every day or two.
-
Step 10: Remove the plastic after germination.
-
Step 11: Provide bright light immediately after germination.
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Step 12: Rotate the plants daily.
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Step 13: Keep temperatures stable.
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Step 14: Water regularly.
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Step 15: Provide fertilizer once the first true leaves emerge.
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Step 16: Transplant seedlings to individual containers.
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Step 17: Harden off your plants.
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Step 18: Transplant your seedlings outdoors.
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Step 19: Maintain your plants.
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Step 20: Prevent fungus infection in young seedlings.
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Step 21: Figure out why tree seeds are not growing.
Detailed Guide
In most cases, you'll want to start your seed indoors.
However, this depends on what you are planting.
For example, lettuce and green beans do better when you sow them outside directly in the ground.
This means you can plant before the spring frosts have passed.
Cold-hardy plants can be planted indoors in late winter or early spring.
Plants that thrive in heat need a later seeding date (mid- or late spring), so the weather is warm when the plants are ready to go outside.
Plants usually take three to six weeks to grow from a seed to a healthy plant ready to be moved outdoors, but some take up to fifteen.
Seeds planted outdoors are vulnerable to disease, insects, and bad weather.
The survival rate will be higher if you care for the young plants indoors.
A seed starting tray from a gardening store is a convenient option, but you can use any small container with drainage holes.
Before reusing an old container, scrub thoroughly with soapy water.
Dip it in a solution of one part household bleach and nine parts hot water, then air dry.
This will kill microorganisms that could harm the seed.Some plants such as lettuce, cucumbers, melons, and sunflowers suffer when transplanted if their roots are disturbed.
You can start these seeds outside instead after the last spring frost, or plant each seed in a separate cell of a "plug tray" and transplant the whole chunk of soil., Making your own is simple, and much cheaper than buying it from a store.
Just mix together equal amounts of perlite, vermiculite, and coir (or peat moss).
This light mix drains quickly to prevent rot, and makes it easy for the sprout to emerge from the surface.Moisten the seed starting mix thoroughly, then fill containers to within ¼" (6mm) of the top.
Use any clean object to gently press the mix into a firm, level surface.
Let excess water drain before you continue.
If you're using a store-bought mix, check whether it contains compost.
If it does, you won't need to fertilize your seedlings. (Don't try to add compost to a homemade mix for your first project — it's more trouble than it's worth.) If you use peat moss instead of coir, add hot water to make it easier to mix in.Since peat moss is acidic, it helps to add garden lime (calcium carbonate) to balance it out.
Try ¼ tsp of lime per gallon of potting mix., If the seed starting mix has dried out, moisten it again before planting.
Check your seed packet for exact spacing and planting depth instructions, or follow these guidelines:
Shared tray, one variety:
Scatter the seeds loosely and evenly across the tray.
Shared tray, multiple varieties:
Scratch shallow rows 1–2 inches (2.5–5cm) apart with a clean ruler.
Drop seeds of each variety into a separate row.
Label each row.
Separate pots or plug trays:
Plant one large seed (e.g. cucumber or melon seed) or two small seeds (e.g. most flower seeds) in each container. , As a rule of thumb, bury seeds to a depth twice the diameter of the seed.
Most tiny seeds need light to germinate, including petunia, lettuce, and snapdragon seeds.
Just leave these on the surface of the mix.
Dry vermiculite or milled sphagnum moss (not peat moss) are ideal for covering seeds, but you can use dry seed-starting mix instead.Sprinkle the material on lightly.
If you press it on hard, the sprout may have trouble breaking through the compact layer. , Seeds are very vulnerable to over- and under-watering.
A layer of plastic wrap or a plastic bag seals will often keep the mix moist until the seeds have germinated.
Most seed trays from garden supply centers come with a plastic cover to keep in moisture.
If your seed trays did not come with a cover, then you can make a miniature greenhouse instead, or grow seedlings in an old, covered aquarium. , If the seed packet doesn't specify a temperature, keep it at daytime temperatures between 65 and 75ºF (18–24ºC), and night temperatures no lower than 55ºF (13ºC).Put a heating pad under the tray if the room is cooler than this.
Most seeds do best in plenty of light, but avoid direct sunlight if the containers are covered in plastic.
Some seeds germinate best in complete darkness, including tomatoes, larkspur, calendula, and coriander.
Block the light with black plastic or cardboard.If you want to maximize success, you can look up your variety's specific temperature needs.
In most cases, though, you'll only lose a few seeds to the "wrong" temperature, or the seeds will take longer to emerge. , If the mix looks dry, place the container in a container of water.
The mix will absorb water from the base of the container.This is less risky than watering from above, which can wash away the seeds or overwater them.
As mentioned before, the plastic is often enough to retain moisture for the whole germination period.
This is just a backup. , Most seeds germinate (sprout) within a couple weeks.
Once sprouts have emerged from the soil, take off the plastic cover (if you were using one).
If you planted in rows in a shared tray, cut strips of plastic or cloth to cover the rows that have not yet sprouted., Move the container to a bright, south-facing window (north-facing in the Southern Hemisphere).
If the temperature or lighting conditions on the windowsill are very different from the last location, move the seeds in several stages, gradually increasing brightness levels.
Sudden changes may kill the plants.
If it is quite cold outside, you may need to place a heat pad between the planters and the window.
Otherwise, the cold will be absorbed through the window and slow the growth of the tiny seedlings.
At far northern or southern latitudes that don't receive much sunlight, place a grow light 6 inches (15 cm) above the seedlings and turn it on for 14–16 hours a day.
Move the lamp farther away as the seedlings grow to avoid burning them., Plants grow toward the light.
If light only comes from one window, the seedlings will lean into it and grow long, weak stems.
Give the containers a quarter turn each day to promote even growth. , Unless your seed packet says otherwise, continue to keep the plants at daytime temperatures between 65 and 75ºF (18–24ºC), and night temperatures no lower than 55ºF (13ºC).
Excessive cold or heat during this stage can cause unhealthy growth patterns, such as weak, "leggy" stems. , The mix must stay moist but not soggy, or the delicate roots will rot or drown (unable to absorb oxygen).
A water bath that lets the container absorb water from the base is ideal, since watering the sprout may break it or encourage disease.
Seeds will quickly die if allowed to dry mid-germination.
Check at least once a day. , The first set of leaves that appear are known as the seed leaves or cotyledons.
The second set of leaves are the first ‘true leaves,’ and a sign that your plant is getting mature and ready for serious growth.
Dilute a balanced fertilizer to ¼ the strength recommended on the label.
Pour it into a tub and place the container in the diluted fertilizer to absorb it from below.
Repeat once a week or as directed by the fertilizer label.
If the seeds were planted in a mix that contained compost, do not fertilize them.
Too many nutrients can cause "burns" or other problems.
You can fertilize at ½ strength once the seedlings are in larger pots, and full strength once they are adults. , If the seedlings are sharing a container, they may need a larger home to prevent them from crowding each other.
However, this isn't necessary for all seeds.
It depends on the variety.
If you do need to thin out the seedlings, delay this delicate process, until the seedling looks sturdy enough to handle it.
Typically, gardeners will only transplant the largest, healthiest seedlings.
You can compost or give away the rest.
Here's how to approach the transfer:
Wash the new container in soapy water, then rinse.
Fill the new container with moist, room temperature potting soil.
Push a hole into it large enough for your seedling's roots.
Gently tease away the starting mix around the seedlings root using a popsicle stick or similar thin tool.
Lift the plant by the topmost leaves.
Do not handle the stem.
Lower the plant into the hole.
Use a pencil to spread out the roots a little, but don't worry if it's not perfect.
Sprinkle moist potting soil over the roots until the seedling is planted to the same depth as before.
Press the soil down lightly.
Avoid changes in temperature and light levels for at least a few days, while the plant is recovering. , ‘Hardening off’ is a process in which you slowly expose your plants to the fluctuating temperature and weather conditions outdoors, so that they don’t suffer from transplant shock.
Start this process two weeks before the outdoor planting date appropriate for your plant:
Lower the temperature indoors slightly.
Water less frequently, but do not let the plants dry out.
Move them outdoors for an hour or two a day, in a shady area protected from wind.
Avoid temperatures below 45ºF (7ºC).Increase the amount of time spent outdoors by an hour or so each day.
Gradually expose the plants to sunlight. (The correct amount of sun depends on the plant and where you plan to move them.) , Once the weather is warm and your plants can handle being outdoors all day, transplant them to a permanent outdoor pot or garden bed.
Follow the specific directions for your plant, since every species has different temperature and sunlight needs.
This is the basic outline only:
When possible, transplant on an overcast morning with minimal wind.
Wet the soil both in your plant's pot and in the new hole.
Carefully transfer the root ball to the new hole.
Spread out the roots as much as you can without breaking them.
Add soil to the same planting depth as before. "Water in" heavily to bring the soil in contact with the roots. , Transplanting is rough on plants, and it can take several weeks before new roots become established.
After the initial watering, keep the plant moist but not soaked.
Protect the plant from strong wind and rain until it's back to its healthy self. , Newly sprouted seedlings die to fungus so often it has its own name: "damping off." Try again with new seeds, and take extra precautions to prevent spores from landing and taking hold:
Use sterile potting mix and clean all containers and tools with a 1:9 ratio of household bleach and water.Sprinkle dry vermiculite or perlite over the surface of the container after planting.
Avoid cool, damp conditions.
If the soil drips water when you squeeze it, it is too wet.
For best results, treat the mix with fungicide, following label instructions. , Many tree seeds, including seeds taken from oranges or apples, need special treatment to trigger germination.
Following the exact instructions for your species will provide best results.
Most seeds of this type need one or both of the following treatments:
Scarification:
Seeds with a hard coat may need it removed or thinned.
Try rubbing with a nail file or nicking it with a knife.
You can even boil some tough seeds to soften the coat.Stratification:
Many tree seeds in nature lie on the ground all winter and germinate in spring.
A few weeks in a cold, damp environment mimics these conditions so the seed "knows" that it should sprout.
Try keeping the seeds between two damp paper towels in the fridge, inside an unsealed zip-locked bag.
About the Author
Isabella Turner
Creates helpful guides on crafts to inspire and educate readers.
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