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If your end-of-summer garden tomatoes are ripening faster than you can keep up with, this might be the easiest way to preserve them! Slow Cooker Garden Tomato Sauce lets you toss any amount of whole tomatoes into the crockpot along with onion, garlic, and fresh basil, simmer all day, and blend into sauce! No chopping, no canning, and your homemade tomato sauce can be used for pasta, pizza, or frozen to preserve your tomato harvest!
- Tomato Harvest - I love growing a lot of varieties of tomatoes every summer, and I don't really love the whole canning process! Making sauce for the freezer, to me, is the most useful way to preserve. While I do think that roasting tomatoes first in the oven, like in my Roasted Cherry Tomato Sauce or this Roasted Tomato Pasta Sauce, does give you the best flavor, this crockpot tomato sauce is definitely the easiest!
- Freezing instead of Canning - When the tomatoes have gotten ahead of you, maybe it just rained and they are starting to split, or you just have so many to use and you don't want to waste them, just pick a bunch and toss them in the crockpot. Large tomatoes, sauce tomatoes, cherry tomatoes, anything can go in and nothing needs to be chopped or peeled. The slow cooker does the work and you can just blend and freeze in jars!
- No chopping the tomatoes - just wash, de-stem, and toss in the crockpot
- Completely hands off - set it and forget it for 6 to 8 hours
- No canning equipment - just freeze in jars or containers
- Flexible recipe - use as many tomatoes as will fit, or just make a smaller batch
- Make it Italian with basil for pasta and pizza, or plain for chili and Mexican dishes
- Naturally gluten-free and vegan
- Love Garden Tomato Recipes? I use a lot of similar but different ways of preserving tomatoes! Try this Freezer Pizza Sauce or my Roasted Tomato Basil Soup. These 21 Ways to Use Garden Tomatoes without Canning will give you lots of ideas for using fresh or freezing!
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Ingredients & Substitutions
The ingredients are so simple you really don't even need a recipe! Just use any amount of tomatoes you have, a few chunks of onion and garlic, fresh basil and season with salt and pepper.
- Garden Tomatoes - Any variety of ripe summer tomatoes can be used, slicers, heirlooms, Romas, cherry tomatoes, or a mix of everything that is ripe and ready. I used 4 pounds of tomatoes, which filled a large crockpot over half full, and made about 5 pint jars of sauce. You can fill your crockpot with more or fewer tomatoes depending on what you want to use up. Red or yellow tomatoes are fine to mix in and will determine the color of the sauce.
- Onion and Garlic - Roughly chop a few pieces of any kind of onion and peel 5 garlic cloves but leave them whole to roast in the tomato juices.
- Salt and Pepper - Just simple seasonings, salt enhances that tomato flavor. You can add a pinch of sugar if you like. I didn't, but a lot of tomato sauces use sugar to balance the acidity of the tomatoes.
- Fresh Basil - Tuck a few sprigs down into the crockpot under the tomatoes so they don't dry out, or you can add a few leaves fresh when blending. Garden basil adds that Italian flavor, or you can leave it out if you want a more basic tomato sauce that can be flavored with whatever you make with it!
See recipe card below for full quantities.
Instructions
This recipe is so quick and easy since the tomatoes don't need to be chopped. Just let them cook in the crockpot all day and blend when you're ready!
Step 1 - Wash the tomatoes really well, removing any stems and cut away any bad spots.
Step 2 - Add the tomatoes to the slow cooker with a few chunks of onion and whole garlic cloves. Sprinkle with salt and pepper. Tuck basil leaves down under the tomatoes so they don't dry out.
Step 3 - Cook on low for 6 to 8 hours.
Use a spoon or ladle to scoop the tomatoes out into a blender. Leaving some of the juice behind in the crockpot will give you a thicker sauce.
Step 4 - I was able to fit the whole batch in my blender, but work in batches if you need to.
You can use the juice to thin it out as needed.
Step 5 - Start blending on low speed. You can blend as smooth or as coarse as you like.
I only blended for a few seconds to keep that rustic texture.
Step 6 - Pour the blended sauce into jars for storing.
Recipe Notes & Tips
- Scoop the Tomato into the Blender - Leaving some of the liquid behind in the crockpot and blending only the solids will give you a thicker, richer sauce. The reserved liquid can be discarded or used as a flavorful tomato broth for soup.
- Use any Amount and any Variety of Tomatoes - This recipe is completely flexible, so there's no need to measure. Use whatever kind of tomatoes you have and use any amount that you want. Four pounds made 4 to 5 pint jars of sauce in a large crockpot. You can fill the crockpot right to the top since the tomatoes cook down significantly.
- Make it Italian or Keep it Plain - With just tomatoes, onion and garlic, this tomato sauce is extremely basic and versatile. You can keep it this way, great for non-Italian dishes like Beef Chili, Chicken Tortilla Soup, or Mexican dishes (the tomato sauce could be a base for salsa or enchilada sauce). Adding basil gives it Italian flavor, great for pasta, Homemade Pizza, or to use in place of crushed tomatoes in recipes like Italian Sausage White Bean Soup with Pasta or Tortellini Pasta Bake with Italian Sausage.
Storage & Freezing
- Storage - Sauce can be stored in a jar or any container in the fridge for up to 5 days.
- Freezer Instructions - Sauce can be frozen to preserve your tomatoes for up to 6 months! You can freeze sauce in glass jars for the perfect serving size.
- Important Precautions when Freezing in Glass Jars:
- You don't need to use canning jars, any glass jars and any size will work.
- Allow sauce to cool slightly before adding to the jars.
- Fill jars only ¾'s full to allow room to expand as it freezes.
- Cool your sauce filled jars completely in the fridge first before moving to the freezer, overnight is best.
- To use, thaw overnight in the fridge before reheating. Never submerge a frozen jar in hot water, it will crack!
- Glass doesn't like sudden temperature changes, so following these steps will avoid cracked jars. If a jar does crack, throw it out, do not try to save the sauce!
- Label and date jars with masking tape and a sharpie!
- Get more freezer ideas with these 27 Homemade Foods to stock in your Freezer!
Recipe FAQs
Use your best judgement here. Garden tomatoes often split after it rains. The tomato is ripe and ready to pick, and then it soaks up so much water from the rain that it outgrows its skin and splits with a crack down the side. If you pick your tomatoes right after the rain and they've just split, they are probably fine to throw in the crockpot. The longer they stay split on the vine, the more likely they are to get black and moldy. If they do, don't use them, or at least cut off the bad part.
If your sauce is still too thin, you can add it to a pot and simmer on the stovetop, stirring often to allow the steam to escape and condense the sauce. The sauce will thicken as it cools, and you may be simmering it after you freeze and thaw it, depending on what you use it for.
No, simply toss everything in the crockpot, the skins and seeds are edible and will get blended into the sauce.
No, this recipe was not made or tested for canning. Freezing is a quick and easy way to preserve this sauce with no special equipment needed.
More Garden Tomato Recipes
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Slow Cooker Garden Fresh Tomato Sauce for the Freezer
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Ingredients
- 4 pounds tomatoes
- ½ onion a few chunks
- 4 cloves garlic whole, peeled
- ½ teaspoon kosher salt
- 10 grinds fresh black pepper
- 2 sprigs fresh basil
Instructions
- Wash your tomatoes well and add them to a slow cooker. You can use any combination of fresh garden tomatoes you have including large tomatoes and cherry tomatoes. Remove any stems or bad spots, no need to chop.
- Add a few chunks of onions, whole peeled garlic cloves, salt and pepper, and a few leaves of basil. Tuck the basil down under the tomatoes so it doesn't dry out.
- Cook on LOW for about 5 to 8 hours.
- Use a large spoon to scoop the tomatoes out into a blender, leaving some of the juice behind. Blend on low speed as smooth or as coarse as you like. Transfer to glass jars, filled only ¾'s full and cool completely in the fridge. Refrigerate for 4 days or freeze for 4 months.
Notes
- Tomatoes - You can use whatever garden tomatoes you have and the amount doesn't really matter, as long as it fits in the slow cooker.
- Blending - Use a regular blender, food processor, or immersion blender. For a thicker sauce, ladle the cooked tomatoes out of the crockpot and into the blender while leaving some of the juices behind. Start blending slowly and don't over blend for a rustic sauce with some texture.
- Freezing in Glass Jars - You can use any jars, they don't need to be canning jars. Fill only ¾'s full to allow room for expansion in the freezer. Cool jars completely in the fridge before freezing. Thaw overnight in the fridge before using. Don't run a frozen jar under water to thaw, it will crack! If a jar does crack, throw it away, don't try to save the sauce.
- How to Use this Sauce - Use as a pasta sauce, pizza sauce or use it in place of marinara or crushed tomatoes in any Italian recipe. If you leave out the basil, it is more of a basic tomato sauce and could be used in chili or Mexican dishes.
- Nutrition Information is for 1 pint jar filled ¾'s full.
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