Direct Seeding vs. Indoor Sowing: Which is Better?
Are you trying to decide between indoor sowing and direct seeding this season? There are many benefits to both, depending on the type of garden you are growing. In this article, gardening expert and former organic farmer Logan Hailey looks at the pros and cons of both sowing methods.
Direct seeding is sowing seeds straight into your garden soil, while transplanting involves starting seeds ahead of time in a protected indoor growing area. Sowing seeds is one of the most exciting parts of growing a garden, but there is a lot of pressure to get things right so the plant can into a strong, fruitful crop,
As you tuck a hopeful little seed into the soil, you can already envision the overflowing baskets of produce that you hope to harvest a few months down the line. Before you empty your seed packets, you may be asking yourself:
- Should you plant the seeds straight into your garden beds?
- Should you start your plants indoors?
- Which plants have to seeded in place and which do better as transplants?
After growing thousands of pounds of fresh produce on over 15 different organic farms, I discovered a few secrets that the most successful farmers and gardeners use to ensure maximum seeding success. Let’s dig into everything you need to know about direct sowing versus seed-starting in trays or pots.
Overview: Direct Seeding vs. Starting Seeds Indoors
Direct sowing is exactly what it sounds like: You plant a seed directly into the garden bed where it will grow for the rest of its lifespan. Long before greenhouses and nurseries, ancient farmers sowed their seeds straight into the soil the same way that nature does.
On the other hand, indoor seed-starting is a modern innovation that allows you to take more control over the germination and early growth process.
Like a baby in a nursery, starting seeds indoors creates a safer, more protected environment that gives the seed a head-start. Once the seedling has developed into a strong adolescent plant, it can be transplanted outside.
Many traditional gardeners believe that seeds should always be planted in place, however they can also have a lower success rate because of conditions out of your control. The weather, soil, rodents, birds, pests, and rainfall can all affect germination rates.
While it requires more equipment and time, indoor seed starting can offer more predictable results. But some crops have sensitive roots that cannot handle transplanting.
|Starting Seeds Indoors
|Seed planted directly in place
|Seed sown in a pot and transplanted later
|Risk of poor germination
|Higher germination rate
|Must wait until the weather has settled
|Get a head-start on seeding before the weather warms
|Straightforward and simple
|More supplies and time required
|Unpredictable outdoor environment
|Climate-controlled indoor environment
|Avoids disrupting the root system
|Risk of transplant shock
|Avoids plants becoming rootbound
|Plants can become rootbound in their containers
|Birds, rodents, and pests may eat the seeds
|Seeds are protected from pests
|Best for root crops (carrots, radishes, parsnips, etc.)
|Best for long-season crops (tomatoes, kale, squash, etc.)
Direct sowing is the “old-fashioned” way of gardening, but it has a wide range of benefits. In fact, some crops have to be directly sown because they can’t handle the root disturbance of transplanting.
Direct seeding means planting a seed straight into the outdoor soil where it will grow for the rest of its life. While transplanted seeds start their lives in a pot, directly-sown seeds never have their roots growth disrupted. This can be highly advantageous for crops that are sensitive to root disturbance, such as carrots or squash.
However, directly sown crops are also exposed to more temperature fluctuation and environmental stress during their early growth. This can lead to direct-sown vegetables growing more slowly than their transplanted counterparts.
Under the right conditions with the proper amount of irrigation, direct-seeded vegetables can do exceptionally well. If you use row fabric and raised beds, the chances of success dramatically increase.
In fact, some crops like carrots have to be direct-sown because they won’t tolerate transplanting. Studies show that direct seeding can be beneficial for some crops and detrimental to others, depending on the variety, conditions, and climate:
- Direct-sown leeks have been found to out-perform transplanted leeks with higher yields.
- This study in India found that direct-sown tomatoes can out-yield transplanted tomatoes.
- However, this study in Poland found that directly seeded tomatoes struggle in cold climates.
- A study with sweet corn found that transplanting provided no advantage over direct sowing.
- Yet another study found that transplanted bell peppers had significantly higher yields.
Ultimately, the success of direct-seeding depends on the crop type and the conditions. Carrots, corn, radishes, and squash may thrive when they are seeded straight into the garden. On the other hand, onions, bell peppers, and tomatoes excel as transplants.
Direct seeding can delay your spring gardening. You can’t get started as early in the season because you have to wait until the weather warms sufficiently for seeds to germinate outdoors.
For long-season crops like peppers or leeks, colder zones may not get enough frost-free days for the plant to grow from seed to maturity outdoors. This is why so many gardeners opt to start long-season crops indoors.
When the average last frost date of the spring arrives, you could be planting out a 5-week-old pepper seedling rather than sowing pepper seeds directly in the ground.
However, there are a few ways to moderate the outdoor seeding environment. You can use row cover or low plastic tunnels over your garden beds to create a cozier microclimate for seeds.
A woven or plastic cover over the bed can buffer the soil against temperature extremes and allow for earlier planting. Still, transplanted crops often out-perform direct-sown crops in many gardens.
Additionally, direct seeding presents more risks to your baby seeds. Rodents, birds, and pests are eager to chomp up seeds that are left out in the garden.
For example, a direct-seeded broccoli plant is more likely to get infested with flea beetles as soon as it emerges from the soil.
A transplanted broccoli will be stronger and more resilient by the time it gets into the garden because it has already grown for several weeks in a protected indoor environment. Again, row cover can help protect seeds from hungry animals in the garden, but it is not fool-proof.
Lastly, inconsistencies in soil texture and moisture can reduce your germination rates. Waterlogged clay soil or drought-prone sandy soils can make it difficult for vegetable seeds to reliably germinate.
Indoor seeding tends to work better because the planting medium is sterile, fine-textured, and evenly moistened.
For the greatest direct sowing success, be sure to incorporate compost, prepare a fine seedbed, and supply continuous moisture.
These crops are most commonly direct seeded:
- Baby lettuce and mesclun mixes
Benefits & Drawbacks of Starting Seeds Indoors
Starting seeds indoors can help you get a head-start to spring planting. As seedlings develop in the cozy protection of a seed tray or pot, they can grow stronger before they are transplanted out into the elements.
While a direct-seeded crop may be more adjusted to the outdoor weather, transplanted crops tend to have earlier yields and higher yields. You can also save money on seeds because germination rates are more reliable in the controlled conditions of a seed-starting tray.
In northern climates with short growing seasons, gardening would be almost impossible without indoor seed-starting. In southern or tropical climates, transplanting is mostly advantageous for the consistent germination and pest protection benefits.
Aside from weather, starting your seeds indoors can reduce the risk of rodents, birds, deer, or bugs eating your baby plants before they get a chance to get established.
Most garden crops do better when they are started indoors and transplanted out into the garden. They get an easier start to life so they can grow larger and faster once out in the field.
As long as the seeds are planted at the proper depth, the protected indoor environment provides more consistent temperatures, finer soil blends, and easier access to water.
All of these factors can ensure more even, reliable seed germination, and early plant success, leading to quicker harvests and higher yields.
Transplanting is usually better than direct seeding because the transplanted crop has a head-start. Imagine that your average last frost date is April 15. On that day, you can go out and direct-sow a pepper seed into the soil. Right next to it, you can transplant a robust pepper seedling that you started indoors 8 weeks ago.
The transplanted pepper will have a HUGE advantage over the seed placed into the soil. It will be stronger, healthier, and more mature, leading to a quicker harvest and higher yields. This is especially true for a slow-growing crop.
In general, larger crops with longer days to maturity do best with transplanting. Broccoli, cauliflower, cabbage, kale, tomatoes, peppers, eggplants, and artichokes all excel when started indoors. Scientific research validates this:
- In a University of Georgia study, transplanted watermelons yielded 40% more melons.
- Transplanted peppers show significantly higher yields and earlier harvests.
- One study with onions found that transplanting significantly improved yields.
- In a study with globe artichoke, transplants had higher yields.
There is even some evidence that transplanted crops are more nutritional than direct-seeded vegetables! Ultimately, transplanting is typically the best choice for beginner gardeners.
While starting seeds indoors and transplanting them later clearly has advantages for crop health, the process still has its drawbacks.
The main downside to indoor seeding is the upfront cost of materials. Fortunately, you only have to invest in that equipment at the beginning of the season. A greenhouse or kitchen grow light setup can last you for a decade or more.
While direct seeding only requires soil, garden beds, and water, indoor seeding calls for more equipment, including:
- Seed-starting trays or pots
- Seed-starting mix or potting mix (soil-less blends can help reduce disease)
- Grow lights (if you don’t have a bright window or greenhouse)
- Plastic greenhouse or glasshouse
- Heating mats (optional, but helpful)
- Ambient temperature regulation
- Humidifiers or domes
- Watering can or hose
Starting seeds indoors also requires significantly more time and effort. Seed trays have to be monitored and watered almost daily. There is more planning and preparation required. You have to worry about light, airflow, heating mats, and humidity levels.
You will also need to properly time your seed-sowing and transplanting schedule. If you transplant too early, the seedling may not have enough roots to handle the move. If you forget to transplant at the proper time, you risk your plants becoming rootbound or overgrowing their containers.
For baby greens or salad mixes, you can also save a lot of time by broadcasting (direct seeding) rather than transplanting. This will give you a medley of quick-harvested young greens.
Root disturbance is another major concern. Crops like brassicas (broccoli, kale, cabbage, cauliflower, etc.) and nightshades (peppers, tomatoes, eggplants, etc.) don’t seem to mind transplanting. In fact, these crops consistently perform better when they are started in trays.
However, squash-family crops (melons, pumpkins, cucumbers, zucchini, etc.) are much more sensitive to root disturbance. Certain root crops like carrots and radishes typically fail at transplanting altogether.
Transplant shock happens when intense weather, drought, harsh sunlight, or another sudden change severely stresses out newly transplanted seedlings. Yellowing, stunted growth, and wilted plants are the key signs of transplant shock. Although most plants recover, this can set them back or sometimes kill them.
To prevent transplant shock, you have to allow a brief period of adjustment before the plants are ready to go outside. This is usually referred to as “hardening off.” You can move strong seedlings onto a porch or protected area for 3-5 days so they can adjust to colder nights and less water before they go out into the garden.
The best crops to start indoors are those with a long growing season and resilient roots. Commonly transplanted vegetables include:
- All peppers
- All tomatoes
- Squash and pumpkins
- Head lettuce
- Swiss chard
At the end of the day, you don’t have to be on “team transplant” or “team direct seed.” The most successful farmers and gardeners combine both methods to grow the best vegetables possible. The key is to choose the ideal method for your crop and your garden.
If you are direct seeding, use tools like row cover and compost to create a better environment for emerging seedlings. If you are starting indoors, be sure that you take extra care to harden-off your plants and protect their roots during transplanting.