In a large heat-resistant bowl (or directly in a heat-resistant serving dish if not unmolding), dissolve the orange jello and a pinch of salt in 1 cup of boiling water, mixing well.
Complete the cup of pineapple juice with the lemon juice and cold water, to make a whole cup of liquid. Add to the dissolved gelatin and mix.
Transfer into a mold (if you wish to serve unmolded) or just refrigerate it in the serving dish until slightly thickened (to ensure the solids will stay suspended), about 20 minutes.
Use a fork to gently fold in grated carrots and pineapple. Distribute evenly, pushing the veggies to the corners of the mold. Refrigerate until fully set, preferably overnight or for at least 4 hours before unmolding.
