Prepare canning jars. Prepare the jars by washing them with hot soapy water. Transfer them to a water bath canner and fill the canner with water until the jars are fully submerged in water. Place over medium heat and bring to a simmer. Put the rings and lids in a saucepan with water. Place over medium-low heat and bring to a simmer. Do not boil.
Boil the strawberries and water. Hull and halve the strawberries. In a large saucepan, combine the strawberries and water. Cook over medium-high heat until the strawberries are soft, about 10 minutes. Mash the strawberries and cook 5 minutes more.
Strain the mixture. Use a fine mesh sieve to strain the strawberry liquid into a bowl, pressing gently on the solids. Discard the solids.
Return the liquid to the saucepan and simmer. Add the sugar and lemon juice to the strained liquid. Heat the mixture over medium heat, stirring until the sugar is completely dissolved. Once the sugar is dissolved, bring the syrup to a boil, then reduce the heat and simmer for 5 minutes.
Fill jars with syrup. Use a ladle and canning funnel to fill the jars with the hot syrup, leaving 1/4 inch headspace.
Wipe jar rims and apply lids. Wipe the rims of the jars with a clean cloth, place the lids on the jars, and screw the bands down until fingertip-tight.
Process. Place the jars in the canning pot and cover them with water. Boil for 10 minutes.
Cool and check seals. Remove the lid from the canner and let the jars cool for 5 minutes. Remove jars from water and let cool for 24 hours. Check the seals before storing.