For faster results, you can  cut off the ends of cucumbers

Boil 1-litre water.
Add 1 tablespoon sugar and 1 tablespoon salt
and 1 tablespoon food vinegar (30%)

If you do not like vinegar, make just salted cucumbers:
1-litre water
2 tablespoon salt
1 tablespoon sugar

Put the cucumbers, garlic, peeled horseradish root, dill roots and flowers and black currant leaves (if any) into the jar.
Add Marinade. Cover, but not airtight. Leave to set in room temperature. After few hours ready to eat!

For longer preservation:

1-litre water
1 tablespoon salt
1 tablespoon sugar
3 tablespoon food vinegar (30%)
(other as previous).
Close airtight