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how many seeds should i plant in a pot

How Many Seeds to Plant Per Hole, Pot, or Cell?

I recently got an email from Sally with a familiar question. It’s the same exact question that I had when I was a beginner gardener and wondered how to start seeds:

“I’m sure this is a silly question, but I always see it recommended to plant more than one seed per hole. But why? I just got a seed starting kit with some seeds and want to make sure I’m using them efficiently. Can you help me out?”

It’s a great question, Sally! Understanding the answer to this question will improve your understanding of gardening and seed starting in general, because the answer hinges on an important concept: seed germination.

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Video Guide

Answer One: Seed Germination Rates

Not all seeds are created equal. Some plant species have higher germination rates than others. Even within a single plant type, some of the seeds are older than others, causing the germination rate to go down.

Imagine you’re growing arugula and the average germination rate is 90%. If you plant a 72 plant starter tray with one arugula seed per insert, you can expect only 65 of those plant inserts to actually germinate (72 x 90%).

Now imagine you plant three arugula seeds per insert. Each of these seeds has a 10% chance of failing, so the probability of them all failing is 10% x 10% x 10% = 0.1%. This means that you are 99.9% likely to have the seeds in that cell germinate. So in a tray of 72 inserts, it would be extremely unlikely you would have any seeds not germinate — barring other factors that affect seed germination.

In short: Planting more seeds per hole increases chance you have perfect germination rates.

Answer Two: Seedling Selection

Just like not all seeds are created equal from a germination standpoint, not all seeds germinate equally. Sometimes you have a seed that shoots off like a rocket and becomes too leggy. If this was the only seed in your insert, you’d be forced to use it.

By planting 2-3 seeds per cell, you allow yourself to luxury of choosing the seedlings that look the strongest. All you have to do is determine which one you like the most, then snip off the other seedlings to kill them.

Exceptions to The Rule

Like most things in gardening, there are always exceptions to this rule of 2-3 seeds per hole.

If you’re planting large seeds like cucumbers, melons, or pumpkins, you should only use one seed per hole. However, you can still plant seeds close together and then thin them out once they’ve established themselves. You just want to avoid crowding these large seeds together so you don’t mess up the germination process.

If you’re growing certain herbs (cilantro, dill, basil), you can get away with planting multiple seeds per hole and leaving them all there as they germinate. These plants can handle being planted right next to each other and basically become one larger, bushier plant.

Now that you know how many seeds to plant per pot, you have a deeper understanding of seed germination in general. For more on seed starting, please check out the simple seed starting for hydroponics guide.

A common question I get by email is, "How many seeds should I plant in each hole or cell?". It's a good question with a great answer — read on to find out!

How Many Seeds Should I Plant per Hole, Cell or Pot?

Seeds per Hole

When starting plants from seed, it is human nature to want to be cautious with the number of seeds planted. Gardeners naturally want to plant exactly the same number of seeds for the number of plants desired. I always thought the same thing too. I always wanted to save as many seeds in order to save money on buying more seeds for the next round of planting or even for next season. However, based on my experience of seed starting every year, I have quickly learned that my instincts were wrong!

So how many seeds should be planted per hole, cell, or pot? In general, two to three seeds should be planted per hole. Seeds do not have 100% germination rates, so not every seed planted will sprout. Overseeding holes, cells, or pots will help ensure that the number of plants you desire will grow (or more!).

Even after reading my recommendation of planting more seeds than necessary, you still may not be convinced. Maybe you’re thinking you want to save as many of your precious seeds as possible. Let’s read on to explore the reasons why over seeding is the best practice.

Why Should I Plant More Seeds Than I Need?

In order to explain the importance of overseeding, let’s walk through a real example. Here’s the situation: Let’s say you know you want a total of six tomato plants this year in your garden and you want to start them all from seed. If you get anything less than six plants, then you will be disappointed. This example will apply with any method you are using to start your seeds, either by sowing in cells, pots, containers or directly in the ground outside.

Not every seed will sprout. Seeds to do not have 100% germination rates. If you have a six cell starter tray for the tomatoes in the example and you plant just one seed per cell, you might end up with only four plants germinating instead of six. However, if you plant more than one seed per cell, you increase your chances of getting at least six plants.

Save space and seed starting mix. Let’s say you know you want six plants, so you think ahead and plant more seeds than you know you’ll need. This time you use twelve cells and plant one seed per cell because you know not every seed will sprout. Planting just one seed per cell is a waste of valuable space under your grow lights and also a waste of extra seed starting mix to fill those cells when you only plan on using six plants. If you put more than one seed in six cells, then you save both space and starting mix. Also, you will end up with the same number of desired plants! Below, we will learn about what to do with the extra growth!

Save money! We already figured out that we can save money on seed starting mix. This strategy will also save money because chances of not having to buy starter plants from a store if seeds fail are increased. Back to our example: If you want six tomato plants and you start just six seeds, then there may be a good chance that only four plants will grow. In this case, you’ll have to go to the store to buy two additional plants. Maybe you’ll just start two more seeds, but remember that this uses up more starting mix and time that you may not have.

If you want to save even more money on seed starting mix you can make your own and learn about in our article DIY Potting Soil and Seed Starting Mix to Save Money.

You get to pick out the strongest plants. Not every seed planted, even if it does germinate, produces a strong and healthy plant. Sometimes a “dud” or a plant that is slower to grow than the others grows. By overseeding, the gardener gets to pick out the best plant in each cell from multiple options, in some cases. This way, the six best plants possible are the ones that will be planted in the garden.

Increase your success the next season by using fresh seeds. Normally when I buy seed packs, even the smallest amounts available are way more than most home gardeners need. Who needs fifty tomato plants (especially of one variety)?! It’s tempting to only use six seeds and not waste all of those precious seeds, but remember, each year that passes, the germination rate of seeds decreases. In other words, seeds do get old – some more quickly than others. Chances of success increase by using fresh seeds, so there is no reason to be stingy to try to make one packet of seeds last multiple years!

Now that you have a better understanding of the benefits of planting more than one seed per hole, cell or pot, I will share with you some strategies sowing different varieties of seeds.

If you are looking for a great place to buy seeds or other general gardening products, True Leaf Market has great prices and I like how you have flexibility on the size of your seed packets!

Examples of Sowing Different Varieties of Seeds

Herbs, Lettuce, Onions

Broadcast Seeding

Whenever I sow herbs, lettuce or onions, I always use the broadcast method. These crops have the smallest types of seeds. Basically, I (or my son) just take a pinch of seeds and sprinkle them around in one cell, pot or row (if planted directly outdoors). Then, I gently mix them into the soil or just add a little bit of soil on top. It is not necessary to plant these types of seeds very d eep !

Herbs such as parsley, oregano, mint, and cilantro are best to plant this way and they don’t even need to be thinned after the seeds sprout.

I plant lettuce this way because I like to use the “cut and come again” approach to harvesting my lettuce rather than trying to grow single large lettuce plants.

Onion Seedlings

For onions, if starting indoors I use this method and densely plant them together. When they are ready to be planted outside, you can pull apart each onion plant fairly easily to space them out in the garden. Onion roots are pretty indestructible, so don’t worry about harming the plant!

Tomatoes, Peppers, Kale, Broccoli

Seed Starting Tomatoes

When it comes to tomatoes, peppers, kale and broccoli, I would consider having medium sized seeds. When they are mature, these plants grow best individually – not together in clumps like the others mentioned above. For each of these types of plants, this is where multiple seeds should be planted per hole, cell, or pot and then thin them out. When the seedlings sprout and start growing, then thin the plants to one strong plant per “spot”.

Cucumbers, Pumpkins, Melons, Peas

Cucumbers, pumpkins, melons and peas have some of the largest seeds. In general, the larger the seed, the smaller amount of seeds should be planted in the same hole or cell. These types of seeds take up more space and grow roots very quickly once germinated. Multiple seeds can still be planted together, but I recommend not planting more than two seeds per hole with these larger seeds.

Now, you have learned how and why to overseed, but the next important step is to thin out those seedlings for optimal growth.

How Do I Thin Out My Seedlings?

Thinning out seedlings can be challenge for most gardeners. Planting seeds and getting them to sprout is hard work! Now, destroy/kill some of them! Ahhhh!! Yes it is hard for me to do too, but it is necessary – especially for the certain plants that need to grow individually and not together in a clump.

When seeds sprout, two leaves come out of the stem. These are called cotyledon. The next leaves that will appear are called the true leaves. They are true leaves because they will stay on the plant, while the cotyledon will eventually fall off on their own.

Around the time when the first true leaves form (or just before that time), it is time to thin plants to one per cell or space in the garden. Try to pick out the best looking plant in each cell or space. Which one is the most green, growing the fastest and growing nice and straight? Find the best one and remove the others by using a pair of thin scissors and cut the plant being removed at the stem at soil level. Do not just pull the plant out because that could disturb the roots of the strong plant.

Hopefully this information has helped you learn a bit more about some of the best practices of seed starting when it comes to overseeding!

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Related Questions

How long does it take for seeds to germinate? On average, most seeds will germinate in one or two weeks as long as conditions are optimal. However, some seeds germinate faster than a week and some varieties may take longer than two weeks.

What soil do I need for starting seeds? Seeds generally like to have a fine mix (no large chunks of material) for best germination. Seed starting mix is available at the store or make it at home by mixing peat moss, vermiculite, perlite and compost/worm castings. Find more information on how I make my own mix from our article DIY Potting Soil and Seed Starting Mix to Save Money.

Do I need a heat mat for starting seeds indoors? While a heat mat is not required, it does help increase success for germination. Most seeds will germinate best at around 70 degrees F. Find the heat mat that I use here.

Do I need a grow light for starting seeds indoors? A grow light is not required if you have enough direct sunlight from a window. I find many people posting pictures online of their “leggy” seedlings next to a window, so I would highly suggest a grow light to start seeds indoors.

So how many seeds should be planted per hole, cell, or pot? In general, two to three seeds should be planted per hole. Seeds do not have 100% germination rates, so not every seed planted will sprout. Overseeding holes, cells, or pots will help ensure that the number of plants you desire will grow (or more!).