How Long Does it Take for Vegetable Seeds to Sprout?

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The two happiest days in a gardeners year is the first harvest and the first seed they plant. Starting your own seeds is a cost effective strategy for any gardener, but waiting for vegetables seeds to sprout can be frustrating. The goal of seed starting is to create ideal conditions for the particular seed you are trying to germinate. By germinating seeds inside you get a head start when temperatures outside are still too cold to direct sow.   

I personally like to see all stages of where my food comes from. I get the best results in my garden when I start from seed. There is nothing wrong with purchasing starts from your local garden center, but there is an extra sense of fulfillment starting from seed. 

Different vegetables have different sprouting times. For most vegetable seeds you should see them sprout through the soil surface within a few weeks. However germination times will vary between vegetables and other factors that I will cover in this post. 

In this post I will show you the best practice for successful germination. There are many ways to start seeds that will all affect germination time. If you give your vegetable seeds optimal conditions you will have a quick germination rate.

Germination Time: 

Below is a list of average germination time of common vegetable seeds you may be starting. Different seeds take longer than others.  .  

• Beets 3-5 days
• Broccoli – 3-5 days
• Cabbage – 3-5 days
• Carrots – 6-10 days
• Cauliflower – 3-5 days
• Celeriac – 11-20 days
• Celery – 6-10 days
• Cucumbers – 3-5 days
• Eggplant – 6-10 days
• Kale – 3-5 days
• Leek – 6-10 days
• Lettuce – 3-5 days
• Muskmelon – 3-5 days
• Okra 6-10 days
• Onion 6-10 days
• Parsley 11-20 days
• Pumpkin – 3-5 days
• Radish – 3-5 days the quickest!
• Rutabaga – 3-5 days
• Snap bean – 6-10 days
• Spinach – 3-5 days
• Squash – 3-5 days
• Sweet corn – 3-5 days
• Swiss chard – 3-5 days
• Parsnip – 11-20 days
• Pea 6-10 days
• Pepper 6 -10 days
• Tomato 6-10 days 
• Turnip – 3-5 days
• Watermelon – 3-5 days

What factors affect germination times?

Now that we know how long it should take for different vegetable seeds to germinate lets talk about why your seeds are taking so long or not coming up at all.

1. Heat: For quick germination you need an ideal temperature. Many seeds will not germinate until soil temperatures reach a certain level. 
2. Water: Keep your seeds moist but not sopping wet. The soil should be saturated but not overly wet. Too much water can cause fungal diseases that can rot your seed.
3. Light: to start seeds you will need a very sunny spot or an artificial lighting system 
4. Seed starting mix
5. Types of seeds
6. New seeds or old seeds – Is your seed viable?   

How to get ideal temperature for germination

Temperature plays a huge roll when starting seed. If you want faster germination invest in a seed heat mat. This mat comes with a thermostat and probe so you can adjust the the soil temperature. If your soil is too cold your seeds will not germinate or will be slow to start. Optimal germination temperature varies between types of vegetable seeds. Most seeds prefer a soil temp between 70-80F or (21-27 celcius) here is a list of popular vegetables to start and their optimal germination temperature:

Tomatoes: 70-80F (21-27C)

Peas: 40-70F (4.44C – 21C) Peas can germinate at a low temperature, but will germinate faster at a warmer temperature. 

Lettuce: 70 – 75 F (21-2389C)

Beet: 85 F (29.5C)

Radish: 85 F (29.5C)

Cabbage:  85 F (29.5)

Cauliflower: 80F (26.5C)

As you can see even the cold season vegetables have a high optimal germination temperatures. It doesn’t mean these seeds will not germinate at lover temps, but for quick reliable germination you want to get your soil warm during the germination period

Just because most seeds like warm temperatures to germinate does not mean the plants themselves need it that warm. For example peas and lettuce are frost tolerant and can survive in the 30’s F. Once the seeds germinate and sprout its a good idea to remove the heat mat. The seedlings do not need such warm soil temperatures anymore and you will end up having to water much more often. 

Water

You are going to want to give your seeds a good amount of water through the sprouting process. Water is needed to get the seed to swell and break through their seed coat. You should not let the seeds dry out, however the soil should never be sitting in water. Unlike plants and seedlings that usually like to get dry between watering when starting seeds I check to see if they need water a couple times a day. They need to be babied in the beginning. I have found using a spray bottle is the best way to water seeds. A pump sprayer or just regular trigger sprayer.  A watering can disrupts the soil too much and can uncover the seeds.

Another good idea is soak your seeds overnight before planting into your soil mix. This will help the water to penetrate the seed coat. Just make sure you don’t leave the seed in the water for longer than 24 hours.   

Light Conditions

Unless you have a greenhouse or very sunny windows you are going to want to get grow lights. Tube fluorescent lighting will work. I have had great success with this grow light. Some seeds need a little light to germinate. Many flower seeds such as poppies, columbine and impatients are sown on the soils surface. Without a little light these seeds will not germinate. 

If you’re not giving your seedling enough light they will get leggy and start stretching for light. The new plants will be too weak to make it out in the garden and not thrive like a seedling would that had plenty of light. Do not deprive your young seedings of light.  

Soil Mix

Using the correct growing medium is crucial for being successful starting from seed. When using a soil mix keep in mind, seeds need abundant water and oxygen to germinate. You want your soil to stay evenly moist, but not boggy or soaked. If the soil goes anaerobic (too wet without oxygen) fungal diseases will occur and your young plants will die or dampen off once they sprout.  You can easily find seed starting mix at your local garden center. A simple seed-starting mix consists of peat moss, perlite, and vermiculite. These components will give your seed the right conditions to germinate successfully.

It is a good idea to add compost and soil amendments to your seed starting mix however these components do not speed the germination process. If you plan on transplanting quickly they are not necessary. 

What are you growing in?    

My preferred method of starting seed is in soil blocks. I go in depth on why I think this is the best way to start seeds in another post. Seed trays are another good option. I have had good luck with peat pots or even egg cartons. The most important aspect is good drainage. Plastic seed trays work great as well!

Is your seed too old? 

Starting with a fresh seed always yields the best germination rates. If you purchase the seeds, the packet will have the growing year the seed was packed for. Every year past this date germination rates go down. You should always take into account some failed germination when working with old seed. I will just plant more when I know I am working with older seed.

 All seeds have an expiration date, but some last longer then others. Most seeds last 3-5 years or even longer when properly stored. Corn and beans for example can be viable for a long time, 10 years or more. On the other hand lettuce, peppers, and onions have a short life span, so you are going to want to plant them in the first couple years you purchase or collect the seeds. 

Storing Vegetable seeds

Make sure you store your seeds in a cool dry place out of sunlight. A sealed glass jar or paper envelope are good options to store your seeds. Make sure your seeds are completely dried before storing them. I store my seeds in my basement. The basement is consitently cool and dark throughout the year.  

Testing viability of seed

If I am using older seed and I want to make sure my seed is still good I will test a few seeds with the paper towel method. 

1. Paper towel method – If there is any question of seed viability I will start seed with the paper towel method. You can quickly see if your seed is viable with this germination test.
   1. First step is to dampen a piece of paper towel 
   2. place your seeds on the damp paper towel and fold the towel over covering the seeds
   3. Put your seeds in either a plastic bag or between two plates
   4. Leave your seeds in a warm spot but not too hot. On a seed heat mat or on top of the fridge works. 
   5. Check on your seeds after a few days and keep the paper towel moist. 
   6. Once they have germinated you can plant them into your seed starting mix. 

Waiting for seeds to germinate takes patients, but if you follow these guide lines i know you will have success. There is nothing more satisfyingly then biting into a summer sun warmed tomato that you grew from a seed you started yourself months back in early spring.