Best way to get rid of them? I've read all sorts of remedies. I want to stick with natural deterants. I heard certain plants/herbs planted near Tomatos will repel the worms...
Some people say just pick them off, but by the time you do that they've already eaten a fair amount of leaves and the tomatoes themselves. I want to keep them off the plants entirely.
No chemicals though.

Deterrent plants include borage, opal basil and marigolds. Dill makes an excellent trap crop. The huge worms are easy to spot on dill plants, and can then be handpicked. Handpicking is the preferred method of control. Although they are huge, they usually aren't numerous. A blast of cold water from the hose will cause them to thrash about and make handpicking easier. - GardenGuides.com
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BASIL: Plant with tomatoes to improve growth and flavor. Basil can be helpful in repelling thrips. It is said to repel flies and mosquitoes. Do not plant near rue.

BORAGE: Companion plant for tomatoes, squash, strawberries and most plants. Deters tomato hornworms and cabbage worms. One of the best bee and wasp attracting plants. Adds trace minerals to the soil and a good addition the compost pile. The leaves contain vitamin C and are rich in calcium, potassium and mineral salts. Borage may benefit any plant it is growing next to via increasing resistance to pests and disease. It also makes a nice mulch for most plants. Borage and strawberries help each other and strawberry farmers always set a few plants in their beds to enhance the fruits flavor and yield. Plant near tomatoes to improve growth and disease resistance. After you have planned this annual once it will self seed. Borage flowers are edible.

CHIVES: Improves growth and flavor of carrots and tomatoes. Keeps aphids help to keep aphids away from tomatoes, mums and sunflowers. Chives may drive away Japanese beetles and carrot rust fly. Planted among apple trees it helps prevent scab and among roses it prevents black spot. You will need patience as it takes about 3 years for plantings of chives to prevent the 2 diseases. A tea of chives may be used on cucumbers and gooseberries to prevent downy and powdery mildews.

DILL: Improves growth and health of cabbage. Do not plant near carrots or caraway. Best friend for lettuce. Attracts hoverflies and predatory wasps. Repels aphids and spider mites to some degree. Also may repel the dreaded squash bug! (scatter some good size dill leaves on plants that are suspect to squash bugs, like squash plants, yeah that's the ticket.) Dill goes well with onions, cabbage, sweet corn and cucumbers. Dill does attract the tomato horn worm so it would be useful to plant it somewhere away from your tomato plants to keep the destructive horn worm away from them. We like to plant it for the swallowtail butterfly caterpillars to feed on. Even their caterpillars are beautiful.

MARIGOLDS: (Calendula): Given a lot of credit as a pest deterrent. Keeps soil free of bad nematodes; supposed to discourage many insects. Plant freely throughout the garden. The marigolds you choose must be a scented variety for them to work. One down side is that marigolds do attract spider mites and slugs.

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French Marigold (T. patula) has roots that exude a substance which spreads in their immediate vicinity killing nematodes. For nematode control you want to plant dense areas of them. There have been some studies done that proved this nematode killing effect lasted for several years after the plants were These marigolds also help to deter whiteflies when planted around tomatoes and can be used in greenhouses for the same purpose. Whiteflies hate the smell of marigolds.
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Mexican marigold (T. minuta) is the most powerful of the insect repelling marigolds and may also overwhelm weed roots such as bind weed! It is said to repel the Mexican bean beetle and wild bunnies! Be careful it can have an herbicidal effect on some plants like beans and cabbage.

MINT: Deters white cabbage moths, ants, rodents, flea beetles, fleas, aphids and improves the health of cabbage and tomatoes. Use cuttings as a mulch around members of the brassica family. It attracts hoverflies and predatory wasps. Earthworms are quite attracted to mint plantings. Be careful where you plant it as mint is an incredibly invasive perennial. We have found that placing mint (fresh or dried) where mice are a problem is very effective in driving them off!

NASTURTIUMS: Plant as a barrier around tomatoes, radishes, cabbage, cucumbers, and under fruit trees. Deters wooly aphids, whiteflies, squash bug, cucumber beetles and other pests of the cucurbit family. Great trap crop for aphids (in particular the black aphids) which it does attract, especially the yellow flowering varieties. Likes poor soil with low moisture and no fertilizer. It has been the practice of some fruit growers that planting nasturtiums every year in the root zone of fruit trees allow the trees to take up the pungent odor of the plants and repel bugs. It has no taste effect on the fruit. A nice variety to grow is Alaska which has attractive green and white variegated leaves. The leaves, flowers and seeds are all edible and wonderful in salads!

PEPPERS, HOT: Chili peppers have root exudates that prevent root rot and other Fusarium diseases. Plant anywhere you have these problems. Teas made from hot peppers can be useful as insect sprays. Hot peppers like to be grouped with cucumbers, eggplant, escarole, tomato, okra, Swiss chard and squash. Herbs to plant near them include: basils, oregano, parsley and rosemary.

PETUNIAS: They repel the asparagus beetle, leafhoppers, certain aphids, tomato worms, Mexican bean beetles and general garden pests. A good companion to tomatoes, but plant everywhere. The leaves can be used in a tea to make a potent bug spray.

POACHED EGG PLANT: Grow poached egg plant with tomatoes, they will attract hover flies and hover flies eat aphids.

TOMATOES: Tomato allies are: asparagus, basil, bean, members of the cabbage family, carrots, celery, chive, cucumber, garlic, head lettuce, marigold, mint, nasturtium, onion, parsley, pepper, marigold, pot marigold and sow thistle. Basil repels flies and mosquitoes, improves growth and flavor. Bee balm, chives and mint improve health and flavor. Borage deters tomato worm, improves growth and flavor. Dill, until mature, improves growth and health, mature dill retards tomato growth. Enemies: corn and tomato are attacked by the same worm. Kohlrabi stunts tomato growth. Keep potatoes and tomatoes apart as they both can get early and late blight contaminating each other.

Source: GoldenHarvestOrganics.com

Thanks. We had Marigolds in the garden last year but unfortunately the closest were about 5 -6' from the tomato plants. We'll surround them with 'golds this year, and put our basil there. Our Basil last year was in a separate garden near the house which is like 200' from the main vegatable garden. We will also get some Borage, which we did not have at all last year. Since we are going to grow our tomatoes in another (new) garden this year we will make sure that all these companion plants are grown with them. The new garden is approx. 24' X 12'and used to be home to a few Black Walnut trees, Wild Rasberries, Wild Chives, Datura Stramonium, and Velvet Leaf. I read something about Datura being both a deterrant to some pests and an attractant.
We have to water by hand (no well yet) so the hose blasting is out, at least for now.

I think the word "blast" was used more to describe the effect of the temperature of the water rather than any pressure. Surely a garden site wouldn't recommend hitting small plants with a high pressure hose.